137 research outputs found

    Initial Filling of Tehri Reservoir — Analysis of Seepage Data

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    Initial Filling of reservoirs in dams, particularly the embankment type, is a very important phase as unusual behaviour / accidents of many dams have been reported during this period. A regular observation / analysis of quantum of seepage vis-à-vis the reservoir level is a significant activity so that any serious development inside the body of dam and foundation / abutments rocks are revealed in advance and remedial measures are taken up timely to prevent catastrophic failures. At Tehri, a 260.5m high earth & rockfill dam has been constructed across river Bhagirathi, a tributary of mighty river Ganga in India. Seepage discharge data of first two years of Initial Filling of Tehri reservoir has been analysed, which has led to a few important conclusions. The Analysis of Seepage data for the Initial Filling of Tehri reservoir is presented in the paper

    Initial Filling of Tehri Reservoir — Analysis of Seepage Data

    Get PDF
    Initial Filling of reservoirs in dams, particularly the embankment type, is a very important phase as unusual behaviour / accidents of many dams have been reported during this period. A regular observation / analysis of quantum of seepage vis-à-vis the reservoir level is a significant activity so that any serious development inside the body of dam and foundation / abutments rocks are revealed in advance and remedial measures are taken up timely to prevent catastrophic failures. At Tehri, a 260.5m high earth & rockfill dam has been constructed across river Bhagirathi, a tributary of mighty river Ganga in India. Seepage discharge data of first two years of Initial Filling of Tehri reservoir has been analysed, which has led to a few important conclusions. The Analysis of Seepage data for the Initial Filling of Tehri reservoir is presented in the paper

    Integrated Approach for Stabilisation of Varunavat Parvat Landslide – A Case Study

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    Uttarkashi Township, located on the toe of the Varunavat Parvat, in the State of Uttarakhand in North India is known for having a history of a number of natural disasters. One of such disaster was a major landslide on the slopes of the Varunavat Parvat, in the year 2003. There had been huge loss of property of residential complexes, office buildings, hotels and many other business apartments. The risk of further such slides continuously hovered over the town which was the serious concern of District and State Authorities. An integrated approach of long term stabilization measures with flattening of slopes with suitable berms, effective drainage arrangement (surface & sub-surface), suitable erosion control measures , multistage protection measures by providing catch pits, wide platforms, retaining walls and construction of tunnel on the national highway for mitigating the rock fall hazards are being adopted, to minimize the impact of disaster in future so that people of Uttarkashi Town can live safely without fear. The paper highlights the description of the problem, probable causes of the Landslide, Geology of the area, stability analysis, measures adopted for averting future landslide and subsequent rock fall hazard

    Synonymous Codon Ordering: A Subtle but Prevalent Strategy of Bacteria to Improve Translational Efficiency

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    Background: In yeast coding sequences, once a particular codon has been used, subsequent occurrence of the same amino acid tends to use codons sharing the same tRNA. Such a phenomenon of co-tRNA codons pairing bias (CTCPB) is also found in some other eukaryotes but it is not known whether it occurs in prokaryotes. Methodology/Principal Findings: In this study, we focused on a total of 773 bacterial genomes to investigate their synonymous codon pairing preferences. After calculating the actual frequencies of synonymous codon pairs and comparing them with their expected values, we detected an obvious pairing bias towards identical codon pairs. This seems consistent with the previously reported CTCPB phenomenon, since identical codons are certainly read by the same tRNA. However, among co-tRNA but non-identical codon pairs, only 22 were often found overrepresented, suggesting that many co-tRNA codons actually do not preferentially pair together in prokaryotes. Therefore, the previously reported co-tRNA codons pairing rule needs to be more rigorously defined. The affinity differences between a tRNA anticodon and its readable codons should be taken into account. Moreover, both within-gene-shuffling tests and phylogenetic analyses support the idea that translational selection played an important role in shaping the observed synonymous codon pairing pattern in prokaryotes. Conclusions: Overall, a high level of synonymous codon pairing bias was detected in 73 % investigated bacterial species

    MycoRRdb: A Database of Computationally Identified Regulatory Regions within Intergenic Sequences in Mycobacterial Genomes

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    The identification of regulatory regions for a gene is an important step towards deciphering the gene regulation. Regulatory regions tend to be conserved under evolution that facilitates the application of comparative genomics to identify such regions. The present study is an attempt to make use of this attribute to identify regulatory regions in the Mycobacterium species followed by the development of a database, MycoRRdb. It consist the regulatory regions identified within the intergenic distances of 25 mycobacterial species. MycoRRdb allows to retrieve the identified intergenic regulatory elements in the mycobacterial genomes. In addition to the predicted motifs, it also allows user to retrieve the Reciprocal Best BLAST Hits across the mycobacterial genomes. It is a useful resource to understand the transcriptional regulatory mechanism of mycobacterial species. This database is first of its kind which specifically addresses cis-regulatory regions and also comprehensive to the mycobacterial species. Database URL: http://mycorrdb.uohbif.in

    Structure and Age Jointly Influence Rates of Protein Evolution

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    What factors determine a protein's rate of evolution are actively debated. Especially unclear is the relative role of intrinsic factors of present-day proteins versus historical factors such as protein age. Here we study the interplay of structural properties and evolutionary age, as determinants of protein evolutionary rate. We use a large set of one-to-one orthologs between human and mouse proteins, with mapped PDB structures. We report that previously observed structural correlations also hold within each age group – including relationships between solvent accessibility, designabililty, and evolutionary rates. However, age also plays a crucial role: age modulates the relationship between solvent accessibility and rate. Additionally, younger proteins, despite being less designable, tend to evolve faster than older proteins. We show that previously reported relationships between age and rate cannot be explained by structural biases among age groups. Finally, we introduce a knowledge-based potential function to study the stability of proteins through large-scale computation. We find that older proteins are more stable for their native structure, and more robust to mutations, than younger ones. Our results underscore that several determinants, both intrinsic and historical, can interact to determine rates of protein evolution

    Proteins with Complex Architecture as Potential Targets for Drug Design: A Case Study of Mycobacterium tuberculosis

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    Lengthy co-evolution of Homo sapiens and Mycobacterium tuberculosis, the main causative agent of tuberculosis, resulted in a dramatically successful pathogen species that presents considerable challenge for modern medicine. The continuous and ever increasing appearance of multi-drug resistant mycobacteria necessitates the identification of novel drug targets and drugs with new mechanisms of action. However, further insights are needed to establish automated protocols for target selection based on the available complete genome sequences. In the present study, we perform complete proteome level comparisons between M. tuberculosis, mycobacteria, other prokaryotes and available eukaryotes based on protein domains, local sequence similarities and protein disorder. We show that the enrichment of certain domains in the genome can indicate an important function specific to M. tuberculosis. We identified two families, termed pkn and PE/PPE that stand out in this respect. The common property of these two protein families is a complex domain organization that combines species-specific regions, commonly occurring domains and disordered segments. Besides highlighting promising novel drug target candidates in M. tuberculosis, the presented analysis can also be viewed as a general protocol to identify proteins involved in species-specific functions in a given organism. We conclude that target selection protocols should be extended to include proteins with complex domain architectures instead of focusing on sequentially unique and essential proteins only

    Global wealth disparities drive adherence to COVID-safe pathways in head and neck cancer surgery

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    The impact of surgical delay on resectability of colorectal cancer: An international prospective cohort study

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    AIM: The SARS-CoV-2 pandemic has provided a unique opportunity to explore the impact of surgical delays on cancer resectability. This study aimed to compare resectability for colorectal cancer patients undergoing delayed versus non-delayed surgery. METHODS: This was an international prospective cohort study of consecutive colorectal cancer patients with a decision for curative surgery (January-April 2020). Surgical delay was defined as an operation taking place more than 4 weeks after treatment decision, in a patient who did not receive neoadjuvant therapy. A subgroup analysis explored the effects of delay in elective patients only. The impact of longer delays was explored in a sensitivity analysis. The primary outcome was complete resection, defined as curative resection with an R0 margin. RESULTS: Overall, 5453 patients from 304 hospitals in 47 countries were included, of whom 6.6% (358/5453) did not receive their planned operation. Of the 4304 operated patients without neoadjuvant therapy, 40.5% (1744/4304) were delayed beyond 4 weeks. Delayed patients were more likely to be older, men, more comorbid, have higher body mass index and have rectal cancer and early stage disease. Delayed patients had higher unadjusted rates of complete resection (93.7% vs. 91.9%, P = 0.032) and lower rates of emergency surgery (4.5% vs. 22.5%, P < 0.001). After adjustment, delay was not associated with a lower rate of complete resection (OR 1.18, 95% CI 0.90-1.55, P = 0.224), which was consistent in elective patients only (OR 0.94, 95% CI 0.69-1.27, P = 0.672). Longer delays were not associated with poorer outcomes. CONCLUSION: One in 15 colorectal cancer patients did not receive their planned operation during the first wave of COVID-19. Surgical delay did not appear to compromise resectability, raising the hypothesis that any reduction in long-term survival attributable to delays is likely to be due to micro-metastatic disease
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