517,176 research outputs found

    Dr. Lin Sun, CAU, March 2013

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    This video is a conversation with Dr. Lin Sun. Dr. Sun talks about an exhibit at the Woodruff Library titled "At The Boundary." Jordan Moore, AUC Woodruff Library, is the interviewer

    Ocena trwałości lin pracujących w górniczych wyciągach szybowych

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    W artykule przedstawiono problematykę trwałości lin nośnych i wyrównawczych eksploatowanych w wybranych szybach kopalń głębinowych. Opisano podstawowe przyczyny zużywania się lin wyciągowych, podano metody oceny zużycia lin stalowych, przedstawiono także kryteria oceny trwałości lin nośnych wyciągowych. Autor zaprezentował również wybrane wyniki z wydłużeń lin nośnych wyciągowych. Artykuł zakończony jest wnioskami wynikającymi z przeprowadzonych badań. Artykuł został także opatrzony zdjęciami przedstawiającymi aparaturę pomiarową, wykorzystywaną do oceny trwałości lin stalowych oraz stalowo-gumowych. W artykule przytoczono zostały kryteria oceny trwałości lin nośnych

    Przedstawianie chińskiej filozofii zachodnim czytelnikom – Lin Yutang jako tłumacz międzykulturowy

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    The article reconstructs selected motifs in the philosophy of Lin Yutang, a twentieth-century Chinese thinker, translator and editor, especially popular in the West, undertaken, as it were, on the margins of his work to explain and popularize Chinese culture and philosophy in the West. Lin reflects on issues such as how to effectively and accurately explain a radically alien civilization to the Western-educated reader, in his or her own language, and who can appoint himself as the representative of Chinese culture at all? As a bilingual author, Lin very accurately shows the state of suspension between two cultures, characteristic of an intercultural interpreter who attempts to simultaneously move within two disproportionate, culturally determined conceptual schemes.W artykule rekonstruuję wybrane wątki refleksji Lin Yutanga, popularnego, zwłaszcza na Zachodzie, dwudziestowiecznego chińskiego myśliciela, tłumacza i redaktora, podejmowanej niejako na marginesie jego pracy na rzecz objaśniania i popularyzowania chińskiej kultury i filozofii na Zachodzie. Lin zastanawia się nad następującymi zagadnieniami, jak: W jaki sposób skutecznie, a jednocześnie trafnie opowiedzieć czytelnikowi wykształconemu w kulturze zachodniej, w jego własnym języku, o radykalnie obcej cywilizacji? Kto w ogóle może mianować samego siebie reprezentantem kultury chińskiej? Jako autor dwujęzyczny Lin nader celnie ukazuje stan zawieszenia, stan bycia pomiędzy, charakterystyczny dla tłumacza międzykulturowego, który podejmuje próbę jednoczesnego poruszania się w obrębie dwóch niewspółmiernych, kulturowo zdeterminowanych schematów pojęciowych

    Model matematyczny wykorzystania lin cumowniczych w manewrowaniu statkiem

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    Benefits and limitations of onboard mooring ropes application to improve a ship manoeuvrability during berthing are discussed. A mathematical model of mooring rope forces is formulated. This has been incorporated in the general ship manoeuvring model for obtaining the real ship motions while a mooring rope is in operation. The simulation output is presented. It appears that the rotational energy absorption performance is largely governed by the location of ship's instant pivot point in relation to the mooring fix point.Przeanalizowano możliwość zastosowania statkowych lin cumowniczych do poprawy sterowności jednostki podczas manewrów cumowania. Sformułowano praktyczny algorytm pozyskiwania oddziaływań lin cumowniczych dla potrzeb symulacji manewrowania. Przedstawiono wyniki symulacji dotyczące redukcji prędkości kątowej wskutek naprężenia liny zamocowanej na dziobie - efektywność takiej operacji zależy w dużym stopniu od wzajemnego położenia chwilowego środka obrotu względem miejsca zamocowania cumy

    Differential roles of the microRNA let-7 in C. elegans tissue development

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    The organs and tissues of the human body comprise of an astonishing variety of cells as different in morphology and function as muscle cells and neurons. Amazingly, despite their different protein contents, they largely contain the identical genomic information. In order to understand the processes that enable this differentiation, we need to determine the underlying regulatory mechanisms. A very recent discovery in this context was the posttranscriptional regulation of gene expression by microRNAs (miRNAs). miRNAs are small RNA molecules that mediate translational repression and degradation of mRNA transcripts through partial complementarity to their 3’ untranslated region (UTR) . Among the first miRNAs to be identified, let-7 stands out for its high conservation in sequence and developmental functions in development throughout the animal kingdom. During my PhD, I studied the role of let-7 in Caenorhabditis elegans in the context of two distinct processes of tissue development, namely differentiation of the epidermis (called hypodermis), and morphogenesis of the vulva. The functions of the let-7 miRNA in formation of the adult cuticle have been extensively studied and are well understood. let-7 controls differentiation of specific, mitotically active epidermal cells by inducing cell cycle exit, fusion, and switch to an adult specific transcriptional program upon repression of targets such as lin-41, daf-12, hbl-1 and let-60/ras. I set out to identify novel interactors of let-7 in a genome-wide RNAi screen for suppression of the lethal let-7 bursting phenotype. Candidates were then verified using fluorescence-based reporter systems for onset of hypodermis differentiation and intensity of repression of a known target. Thereby, I was able to validate a whole set of novel members of the let-7 network, comprising genes downstream in the pathway as well as potential regulators of let-7 activity. Notably, both groups of repressors contain factors required for cell cycle progression and mitosis, which indicates an active crosstalk between let-7 and the cell-cycle machinery. In a second project, I explored the molecular basis for the prominent let-7 vulval bursting phenotype. Despite the absence of overproliferation or any other obvious phenotype in vulval morphogenesis, I was able to show that let-7 activity is required in the vulva, and that its major function in this context is repression of a single target, namely lin-41. Disruption of let-7 binding to lin-41 through modification of the let-7 complementary sites by CRISPR/Cas9 mediated genome editing suffices to trigger the bursting phenotype, proving that repression of a single target is the key function of the miRNA in this context. In summary, my work shows that while both differentiation of hypodermis as well as vulval integrity are mediated through repression of lin-41, the downstream effect of this regulation seem to differ, suggesting that let-7 can be wired to control distinct processes depending on the cellular context. With respect to the latest findings both in C. elegans as well as in mammals, it will be interesting to determine if this depends on differential molecular functions of LIN-41 in the two tissues

    A single E-box in the <i>Cel-lin-3</i> CRM is not sufficient for <i>lin-3</i> expression in the anchor cell of <i>C</i>. <i>elegans</i>.

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    (A) New cis-regulatory lin-3 alleles with deleted E-boxL and NHR or NHR and E-boxR. (B) Quantification of vulval induction in these new mutants. Note the complete absence of any induction in the recovered lin-3 alleles (n>30). Scorings of lin-3(1417) animals are the same as those reported in Fig 5 and are used here to indicate that this mutation leads to vulval hypo-induction rather than no induction at all. (C-D) smFISH in lin-3(mf72) (C) and N2 (D) animals. Green spots correspond to lin-3 transcripts and red spots to lag-2 that is used as an anchor cell marker. Blue is DAPI staining of nuclei. Note the absence of lin-3 expression in the anchor cell in the lin-3(mf72) mutant animal. Absence of lin-3 signal in the anchor cell was also confirmed for the other lin-3 alleles.</p

    The stem cell E3-ligase Lin-41 promotes liver cancer progression through inhibition of microRNA-mediated gene silencing

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    Lin-41 is a stem cell-specific E3 ligase and a known target of the tumour suppressor microRNA (miRNA) let-7. Lin-41 was recently reported to mediate ubiquitylation and degradation of the miRNA pathway protein Ago2. We demonstrate that Lin-41 is over-expressed in hepatocellular carcinoma (HCC). Lin-41 over-expression correlates with high a-fetoprotein level, high tumour grade and high tumour stage and predicts early tumour recurrence. Lin-41 is a strong predictor of poor long-term survival for patients with HCC. Lin-41 knock-down by RNA interference in HCC cell lines Huh7 and Hep3B suppressed proliferation in vitro and reduced in vivo tumour growth in NOD/SCID mice. On the other hand, over-expression of Lin-41 in the HCC cell line SK-Hep1 enhanced tumourigenicity. Over-expression and knock-down of Lin-41 led to inverse changes in the levels of Ago1 and Ago2 proteins. Over-expression of Ago1 and Ago2 reduced in vivo tumour growth. Lin-41 over-expression suppressed let-7 activity in HCC cell lines and expression of Lin-41 enhanced the expression of let-7-regulated oncogenes c-Myc, Lin-28B, HMGA2 and type 1 insulin-like growth factor receptor (IGF1R). Expression of Lin-28B and c-Myc enhanced the expression of Lin-41. Chromatin immunoprecipitation and reporter assays revealed direct association of c-Myc with the Lin-41 promoter, resulting in transcriptional transactivation. Our results indicate that Lin-41 plays an important role in the growth of HCC by regulating RISC complex proteins Ago1 and Ago2 to inhibit miRNA-mediated gene silencing and promote the expression of oncogenic proteins. Lin-41 is also a strong prognostic factor for patients with HCC. Copyright (C) 2012 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd
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