188 research outputs found

    ANALISA KESELAMATAN DAN KESEHATAN KERJA DRILLING DI PT. HANSINDO MINERAL PERSADA KECAMATAN SUNGAI PINYUH KABUPATEN MEMPAWAH KALIMANTAN BARAT

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    PT. Hansindo Mineral Persada (PT. Hansindo) salah satu perusahaan yang berkiprah dibidang pertambangan batu granit. PT. Hansindo melakukan penambangan batu granit di Desa Peniraman, Kecamatam Sungai Pinyuh, Kabupaten Mempawah, Provinsi Kalimantan Barat. Pengeboran artinya aktivitas yang pertama kali dilakukan pada suatu kegiatan peledakan batuan sebagai akibatnya pekerjaan ini mengandung risiko bagi setiap elemen yang terlibat. Oleh karena itu perlu dilakukan analisisi potensi bahaya karena masalah Kesehatan dan Keselamatan Kerja (K3) harus mendapatkan perhatian, agar dapat meminimalkan potensi bahaya dan risiko kecelakaan akibat kerja. Tujuan penelitian melakukan identifikasi potensi bahaya dan risiko pada psroses drilling dengan penelitian kualitatif teknik yang digunakan dalam pengumpulan data yaitu observasi dan pengisian kuesioner dan menggunakan metode HIRARC dengan waktu lebih kurang 30 hari untuk melakukan identifikasi bahaya, penilaian risiko dan melakukan upaya pengendalian risiko, dalam meminimalisir potensi bahaya dan risiko kecelakaan. berdasarkan hasil observasi dan kuesioner terdapat 7 kegiatan drilling dan 17 potensi bahaya dan risiko, dan 18 rekomendasi pengendalian bahaya dan risiko yang penerapannya berdasarkan OHSAS 18001:2007 berupa eliminasi, substitusi, engineering control, admistratif dan alat pelindung diri

    ANALISIS KUAT TEKAN TERHADAP WAKTU STAND-UP C1-G PERTAMBANGAN BAWAH TANAH PT. NAL SAWAHLUNTO SUMATERA BARAT

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    Daerah penelitian (PT NAL) terletak di Desa Salak, Kecamatan Talawi, Kota Sawahlunto. Tujuan penelitian ini adalah untuk menganalisis kuat tekan batuan dan waktu stand-up yang diperlukan dalam perencanaan penggalian dan pemasangan dukungan penambangan bawah tanah di PT. NAL. Pengumpulan data dalam penelitian ini menggunakan observasi lapangan dan pengujian laboratorium. Metode pemecahan masalah dalam penelitian ini didasarkan pada klasifikasi massa batuan dari Bienalwski (1973) Sistem Nilai Massal Batu atau RMR yang terdiri dari kekuatan tekan UCS, jarak diskontinuitas, Rock Quality Designation (RQD), kondisi solid, kondisi air tanah dan orientasi pemegatan. Hasil analisis kekuatan uji kuat tekan batuan utuh, terlihat bahwa batuan terowongan memiliki nilai UCS 8,835 Mpa (lemah) untuk batu pasir, 13.367 Mpa (lemah) untuk batu lanau dan 4,620 Mpa (sangat lemah) untuk batubara. Berdasarkan sifat fisik, diketahui bahwa setiap batuan memiliki nilai porositas yang rendah. Analisis geomekanik memberikan nilai tertimbang Rock Mass Rating (RMR) dengan kualitas massa batuan kelas II (rock baik) untuk tiga jenis massa batuan. Analisis menggunakan grafik waktu stand-up, lamanya batu dapat menahan self-stress tanpa stand-up time untuk batupasir ± 2500 jam (3 bulan 12 hari) dengan bentang 8 m, batu lanau ± 2000 jam (2 bulan 21 hari ) dengan bentang 8 m dan batu bara ± 5000 jam (6 bulan 27 hari) dengan rentang 6,8 m

    Concurrent validity of self-rating scale of self-directed learning and self-directed learning instrument among Italian nursing students

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    BACKGROUND: Self-Directed Learning develops when students take the initiative for their learning, recognising needs, formulating goals, identifying resources, implementing appropriate strategies and evaluating learning outcomes. This should be seen as a collaborative process between the nurse educator and the learner. At the international level, various instruments have been used to measure Self-Directed Learning abilities (SDL), both in original and in culturally-adapted versions. However, few instruments have been subjected to full validation, and no gold standard reference has been established to date. In addition, few researchers have adopted the established tools to assess the concurrent validity of the emerging new tools. Therefore, the aim of this study was to measure the concurrent validity between the Self-Rating Scale of Self-Directed Learning (SRSSDL_Ita) - Italian version and the Self-Directed Learning Instruments (SDLI) in undergraduate nursing students. METHODS: A concurrent validity study design was conducted in a Bachelor level nursing degree programme located in Italy. All nursing students attending the first, second or third year (n=428) were the target sample. The SRSSDL_Ita, and the SDLI were used. The Pearson correlation was used to determine the concurrent validity between the instruments; the confidence of intervals (CI 95%) bias-corrected and accelerated bootstrap (BCa), were also calculated. RESULTS: The majority of participants were students attending their first year (47.9%), and were predominately female (78.5%). Their average age was 22.5\ub14.1. The SDL abilities scores, as measured with the SRSSDL_Ita (min 40, max 200), were, on average, 160.79 (95% CI 159.10-162.57; median 160); while with the SDLI (min 20, max 100), they were on average 82.57 (95% CI 81.79-83.38; median 83). The Pearson correlation between the SRSSDL_Ita and SDLI instruments was 0.815 (CI BCa 95% 0.774-0.848), (p=0.000). CONCLUSIONS: The findings confirm the concurrent validity of the SRSSDL_Ita with the SDLI. The SRSSDL_Ita instrument can be useful in the process of identifying Self-Directed Learning abilities, which are essential for students to achieve the expected learning goals and become lifelong learners

    Inhibition of Autoimmune Diabetes in NOD Mice by miRNA Therapy.

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    Autoimmune destruction of the pancreatic islets in Type 1 diabetes is mediated by both increased proinflammatory (Teff) and decreased regulatory (Treg) T lymphocytes resulting in a significant decrease in the Treg:Teff ratio. The non-obese diabetic (NOD) mouse is an excellent in vivo model for testing potential therapeutics for attenuating the decrease in the Treg:Teff ratio and inhibiting disease pathogenesis. Here we show for the first time that a bioreactor manufactured therapeutic consisting of a complex of miRNA species (denoted as TA1) can effectively reset the NOD immune system from a proinflammatory to a tolerogenic state thus preventing or delaying autoimmune diabetes. Treatment of NOD mice with TA1 resulted in a systemic broad-spectrum upregulation of tolerogenic T cell subsets with a parallel downregulation of Teff subsets yielding a dramatic increase in the Treg:Teff ratio. Moreover, the murine-derived TA1 was highly effective in the inhibition of allorecognition of HLA-disparate human PBMC. TA1 demonstrated dose-responsiveness and exhibited equivalent or better inhibition of allorecognition driven proliferation than etanercept (a soluble TNF receptor). These findings demonstrate that miRNA-based therapeutics can effectively attenuate or arrest autoimmune disease processes and may be of significant utility in a broad range of autoimmune diseases including Type 1 diabetes

    Anticancer activity of an extract from needles and twigs of Taxus cuspidata and its synergistic effect as a cocktail with 5-fluorouracil

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    <p>Abstract</p> <p>Background</p> <p>Botanical medicines are increasingly combined with chemotherapeutics as anticancer drug cocktails. This study aimed to assess the chemotherapeutic potential of an extract of <it>Taxus cuspidata </it>(<it>TC</it>) needles and twigs produced by artificial cuttage and its co-effects as a cocktail with 5-fluorouracil (5-FU).</p> <p>Methods</p> <p>Components of <it>TC </it>extract were identified by HPLC fingerprinting. Cytotoxicity analysis was performed by MTT assay or ATP assay. Apoptosis studies were analyzed by H & E, PI, TUNEL staining, as well as Annexin V/PI assay. Cell cycle analysis was performed by flow cytometry. 5-FU concentrations in rat plasma were determined by HPLC and the pharmacokinetic parameters were estimated using 3p87 software. Synergistic efficacy was subjected to median effect analysis with the mutually nonexclusive model using Calcusyn1 software. The significance of differences between values was estimated by using a one-way ANOVA.</p> <p>Results</p> <p><it>TC </it>extract reached inhibition rates of 70-90% in different human cancer cell lines (HL-60, BGC-823, KB, Bel-7402, and HeLa) but only 5-7% in normal mouse T/B lymphocytes, demonstrating the broad-spectrum anticancer activity and low toxicity to normal cells of <it>TC </it>extract <it>in vitro</it>. <it>TC </it>extract inhibited cancer cell growth by inducing apoptosis and G<sub>2</sub>/M cell cycle arrest. Most interestingly, <it>TC </it>extract and 5-FU, combined as a cocktail, synergistically inhibited the growth of cancer cells <it>in vitro</it>, with Combination Index values (CI) ranging from 0.90 to 0.26 at different effect levels from IC50 to IC90 in MCF-7 cells, CI ranging from 0.93 to 0.13 for IC40 to IC90 in PC-3M-1E8 cells, and CI < 1 in A549 cells. In addition, the cocktail had lower cytotoxicity in normal human cell (HEL) than 5-FU used alone. Furthermore, <it>TC </it>extract did not affect the pharmacokinetics of 5-FU in rats.</p> <p>Conclusions</p> <p>The combinational use of the <it>TC </it>extract with 5-FU displays strong cytotoxic synergy in cancer cells and low cytotoxicity in normal cells. These findings suggest that this cocktail may have a potential role in cancer treatment.</p

    Structure-Activity Determinants in Antifungal Plant Defensins MsDef1 and MtDef4 with Different Modes of Action against Fusarium graminearum

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    Plant defensins are small cysteine-rich antimicrobial proteins. Their three-dimensional structures are similar in that they consist of an α-helix and three anti-parallel β-strands stabilized by four disulfide bonds. Plant defensins MsDef1 and MtDef4 are potent inhibitors of the growth of several filamentous fungi including Fusarium graminearum. However, they differ markedly in their antifungal properties as well as modes of antifungal action. MsDef1 induces prolific hyperbranching of fungal hyphae, whereas MtDef4 does not. Both defensins contain a highly conserved γ-core motif (GXCX3–9C), a hallmark signature present in the disulfide-stabilized antimicrobial peptides, composed of β2 and β3 strands and the interposed loop. The γ-core motifs of these two defensins differ significantly in their primary amino acid sequences and in their net charge. In this study, we have found that the major determinants of the antifungal activity and morphogenicity of these defensins reside in their γ-core motifs. The MsDef1-γ4 variant in which the γ-core motif of MsDef1 was replaced by that of MtDef4 was almost as potent as MtDef4 and also failed to induce hyperbranching of fungal hyphae. Importantly, the γ-core motif of MtDef4 alone was capable of inhibiting fungal growth, but that of MsDef1 was not. The analysis of synthetic γ-core variants of MtDef4 indicated that the cationic and hydrophobic amino acids were important for antifungal activity. Both MsDef1 and MtDef4 induced plasma membrane permeabilization; however, kinetic studies revealed that MtDef4 was more efficient in permeabilizing fungal plasma membrane than MsDef1. Furthermore, the in vitro antifungal activity of MsDef1, MsDef1-γ4, MtDef4 and peptides derived from the γ-core motif of each defensin was not solely dependent on their ability to permeabilize the fungal plasma membrane. The data reported here indicate that the γ-core motif defines the unique antifungal properties of each defensin and may facilitate de novo design of more potent antifungal peptides

    The Novel Candida albicans Transporter Dur31 Is a Multi-Stage Pathogenicity Factor

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    Candida albicans is the most frequent cause of oral fungal infections. However, the exact pathogenicity mechanisms that this fungus employs are largely unknown and many of the genes expressed during oral infection are uncharacterized. In this study we sought to functionally characterize 12 previously unknown function genes associated with oral candidiasis. We generated homozygous knockout mutants for all 12 genes and analyzed their interaction with human oral epithelium in vitro. Eleven mutants caused significantly less epithelial damage and, of these, deletion of orf19.6656 (DUR31) elicited the strongest reduction in pathogenicity. Interestingly, DUR31 was not only involved in oral epithelial damage, but in multiple stages of candidiasis, including surviving attack by human neutrophils, endothelial damage and virulence in vivo. In silico analysis indicated that DUR31 encodes a sodium/substrate symporter with 13 transmembrane domains and no human homologue. We provide evidence that Dur31 transports histatin 5. This is one of the very first examples of microbial driven import of this highly cytotoxic antimicrobial peptide. Also, in contrast to wild type C. albicans, dur31Δ/Δ was unable to actively increase local environmental pH, suggesting that Dur31 lies in the extracellular alkalinization hyphal auto-induction pathway; and, indeed, DUR31 was required for morphogenesis. In agreement with this observation, dur31Δ/Δ was unable to assimilate the polyamine spermidine
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