1,257 research outputs found

    Nuclear RNA Surveillance in \u3cem\u3eSaccharomyces cerevisiae\u3c/em\u3e: Trf4p-dependent Polyadenylation of Nascent Hypomethylated tRNA and an Aberrant Form of 5S rRNA

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    1-Methyladenosine modification at position 58 of tRNA is catalyzed by a two-subunit methyltransferase composed of Trm6p and Trm61p in Saccharomyces cerevisiae. Initiator tRNA (tRNAiMet) lacking m1A58 (hypomethylated) is rendered unstable through the cooperative function of the poly(A) polymerases, Trf4p/Trf5p, and the nuclear exosome. We provide evidence that a catalytically active Trf4p poly(A) polymerase is required for polyadenylation of hypomethylated tRNAiMet in vivo. DNA sequence analysis of tRNAiMet cDNAs and Northern hybridizations of poly(A)+ RNA provide evidence that nascent pre-tRNAiMet transcripts are targeted for polyadenylation and degradation. We determined that a mutant U6 snRNA and an aberrant form of 5S rRNA are stabilized in the absence of Trf4p, supporting that Trf4p facilitated RNA surveillance is a global process that stretches beyond hypomethylated tRNAiMet. We conclude that an array of RNA polymerase III transcripts are targeted for Trf4p/ Trf5p-dependent polyadenylation and turnover to eliminate mutant and variant forms of normally stable RNAs

    Measurement of Dust Optical Properties in Coalsack

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    We have used FUSE and Voyager observations of dust scattered starlight in the neighborhood of the Coalsack Nebula to derive the optical constants of the dust grains. The albedo is consistent with a value of 0.28±0.040.28 \pm 0.04 and the phase function asymmetry factor with a value of 0.61±0.070.61 \pm 0.07 throughout the spectral range from 900 -- 1200 \AA, in agreement with previous determinations as well as theoretical predictions. We have now observed two regions (Ophiuchus and Coalsack) with intense diffuse background radiation and in both cases have found that the emission is due to light from nearby hot stars scattered by a relatively thin foreground cloud, with negligible contribution from the background molecular cloud.Comment: Total 19 pages, Figures 9, Accepted for publication in Astrophysical Journa

    VALUE ADDITION OF ERI SILK YARNS WITH ALLAMANDA GRANDIFLORA - A NATURAL COLOURANT

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    Eri silk is one of the four varieties of silk mostly available in northeastern region of India. Recent trends in the world market of silk revealed that eri silk had tremendous potential as it was gifted with unique properties of protecting human body from some aliments as well as its use as fashionable dress and furnishing materials besides providing comfort of warmth. To suit the norms of the present national and international market, dyeing eri silk with natural dyes contributes to its value chain. The information on dyeing eri silk with natural dyes is very meager and requires to be established. New source such as Allamanda grandiflora was not used for dyeing textiles as per the available literature. Effort was made to standardise variables involved in extraction of the dyes and dyeing eri silk yarns. The standardisation procedures described under materials and methods were used and the evaluation was based on colour strength (K/S values) measured using colour flex spectrophotometer. Among the three mordanting methods, Pre mordanting method exhibited better   results compare with simultaneous and post mordanted samples. Among the five mordants, alum and chitin mordanted samples exhibited good fastness followed by tartaric acid, ferrous sulphate and stannous chloride mordanted samples

    Ferromagnetism in nanoscale BiFeO3

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    A remarkably high saturation magnetization of ~0.4mu_B/Fe along with room temperature ferromagnetic hysteresis loop has been observed in nanoscale (4-40 nm) multiferroic BiFeO_3 which in bulk form exhibits weak magnetization (~0.02mu_B/Fe) and an antiferromagnetic order. The magnetic hysteresis loops, however, exhibit exchange bias as well as vertical asymmetry which could be because of spin pinning at the boundaries between ferromagnetic and antiferromagnetic domains. Interestingly, like in bulk BiFeO_3, both the calorimetric and dielectric permittivity data in nanoscale BiFeO_3 exhibit characteristic features at the magnetic transition point. These features establish formation of a true ferromagnetic-ferroelectric system with a coupling between the respective order parameters in nanoscale BiFeO_3.Comment: 13 pages including 4 figures; pdf only; submitted to Appl. Phys. Let

    Negative values expressed in Vannadasan's work

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    Tamil literature has a continuity of more than two thousand years. Literature is the gateway to the present and the future for oneself and one's own society. It helps to know the past society and living conditions. Creativity can convey the ideas people need or people's thoughts. The experience a person gets while learning such creativity sometimes causes positive thoughts and negative thoughts. Learning to think and act positively is essential to change negative situations. Only a man who has seen many failures can create a steady path of success. In this situation, Vannadasan is a great creator who is moving forward in life by taking positive experiences from fellow human beings. If one wants to excel as a high man, it is better that the thoughts that appear in the heart also be high. One should agree with the people living in the society with affection and attachment. It is known in the way of Vannadhasan's work that when we help each other and understand each other's feelings, relationships improve and we act in such a way that the values ​​are identified by us

    Involvement of Serine Threonine Protein Kinase, PknL, from Mycobacterium Tuberculosis H37Rv in Starvation Response of Mycobacteria

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    The adaptation to nutrient depletion in bacteria involves a highly organized series of intracellular events that enable them to adapt to starvation conditions. The regulatory effect of serine threonine protein kinase, PknL, from Mycobacterium tuberculosis strain H37Rv was investigated under nutrient deprived conditions that simulate circumstances leading to latency. Recombinant PknL was expressed in Mycobacterium smegmatis strain mc2155 in its wild type and mutant forms. In vitro growth kinetics experiments revealed that clone expressing active PknL had a significant growth advantage under nutrient limiting conditions. Experiments were conducted to ascertain the in silico predictions of the involvement of PknL in regulating glutamine metabolism in mycobacteria. Furthermore, a role for PknL in cell wall biogenesis/cell division was shown by scanning electron microscopy

    Software Test Automation with Robot Framework

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    Testing is a crucial activity in Software Development Process. It is to examine & modify source code. Effective Testing produces high quality software. To improve the quality and the efficiency of software testing, software automation test has been used widely during the software testing. This paper discusses the advantages of testing tools in software test automation, with the Robot framework

    Extended Apriori for association rule mining: Diminution based utility weightage measuring approach

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    The field of Association rule mining is a dynamic area for innovation of knowledge through which uncountable procedures have been expounded. Recently, by including significant components viz. value (utility), volume of items (weight) etc, the researchers have enhanced the quality of association rule mining for industry by bringing out the association designs. In this note, a proficient methodology has been put forward based on weight factor and utility for effective digging out of important association rules. At the very beginning, a traditional Apriori algorithm has been utilized that make use of the anti-monotone property which states that if n items are recurring continuously then n-1 items should also recur by which the scores of weightage(W-Gain), utility(U-Gain) and diminution(D-sum), are derived at. Eventually, we derive a subset of important association rules through which EUW-Score is generated. The tentative outcome demonstrates the effectiveness of the methodology in generating high utility association rules that is profitably used for the business improvement
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