304 research outputs found

    The Non-Destructive and Nano-Microstructural Characterization of Thermal-Barrier Coatings

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    The durability of thermal barrier coatings (TBCs) plays an important role in the service reliability and maintainability of hot-section components in advanced turbine engines for aerospace and utility applications. Photostimulated luminescence spectroscopy (PSLS) and electrochemical impedance spectroscopy (EIS) are being concurrently developed as complimentary nondestructive evaluation (NDE) techniques for quality control and liferemain assessment of TBCs. This paper discusses recent achievements in understanding the residual stress, phase constituents, and electrochemical resistance (or capacitance) of TBC constituents—with an emphasis on the thermally grown oxide. Results from NDE by PSLS and EIS are correlated to the nano- and microstructural development of TBCs

    The Non-Destructive and Nano-Microstructural Characterization of Thermal-Barrier Coatings

    Get PDF
    The durability of thermal barrier coatings (TBCs) plays an important role in the service reliability and maintainability of hot-section components in advanced turbine engines for aerospace and utility applications. Photostimulated luminescence spectroscopy (PSLS) and electrochemical impedance spectroscopy (EIS) are being concurrently developed as complimentary nondestructive evaluation (NDE) techniques for quality control and liferemain assessment of TBCs. This paper discusses recent achievements in understanding the residual stress, phase constituents, and electrochemical resistance (or capacitance) of TBC constituents—with an emphasis on the thermally grown oxide. Results from NDE by PSLS and EIS are correlated to the nano- and microstructural development of TBCs

    Inheritance patterns, consanguinity & risk for asthma

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    Background & Objectives: Family history is an important risk factor for the development of asthma, contingent upon genetic and environment interaction. Since there is paucity of data on asthma inheritance in Indian population, the present study was undertaken to investigate the inheritance patterns of asthma and the effect of family history and consanguineous marriage on asthma inheritance. Methods: A total of 200 families, 100 index children and 100 index adults with clinically diagnosed asthma, along with 400 non-asthmatic children and adults as controls were selected for the present study. Information about the family history of each patients and controls was collected and analyzed pedigrees were also constructed. Results: A history of asthma in any member of the family was observed in 44.5 per cent of cases and 5.3 per cent of controls (P<0.001). A differential risk of developing asthma was noted in family history of asthma in different first and second degree relatives of children and adult patients. Consanguineous marriage was also noted in parents in 24.5 per cent of cases and 12.3 per cent of controls (P<0.001). The most common mode of asthma inheritance was recessive. Interpretation & Conclusions: Our results showed that consanguineous marriage and family history of asthma are important determinants in the development of asthma in the offspring

    Rickettsial neglected zoonoses: prevalence of scrub typhus at central Karnataka

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    Background: Fever of unknown Origin (FUO) has many multiple causes such as enteric fever, malaria, dengue, tuberculosis, brucellosis. But scrub typhus is less known cause in Indian scenario. The present study reports the prevalence of scrub typhus at central Karnataka and compares the sensitivity and specificity of Weil-Felix test and the IgM ELISA in the detection of infection.Methods: 368 serum samples of FUO cases were collected. Weil-Felix test was performed and also analyzed for IgM antibodies to Orienta tsutsugamushi by IgM ELISA test along with haematological and biochemical investigations.Results: Out of 368 patients of fever of unknown origin, 94 cases were positive by OXK antigens by Weil Felix test and 61 were positive by ELISA test for ST IgM antibodies. Fever was the most common clinical presentation occurring in ST IgM ELISA positive cases, followed by myalgia in 90.1% cases, headache in 77%, hepatomegaly in 65.5%, splenomegaly in 62.2% and rashes were seen in 29.5% patients. Eschar was seen in 13.1% patients, pneumonia in 3.2% and meningo-encephalitis in 1.6%. Sensitivity and specificity of WFT in relation to IgM ELISA at a titre of 160 was 81.97% and 85.67% respectively.Conclusions: With the growing number of cases detected in India, scrub typhus is fast emerging as a public health threat and also due to limited diagnostics leading to underreporting, Weil Felix test could be used in adjunct with Enzyme-linked immunosorbent assay and blood parameters in the diagnosis of rickettsial diseases

    Structure Prediction and Active Site Analysis of New H1N1 Neuraminidase:Target for Antiviral Drug Design

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    Abstract: The H1N1 viral envelope protein neuraminidase encoded by NA gene plays a key role in the pathogenesis of swine flu. The active site of the neuraminidase protein is targeted by presently available antiviral drugs. The influenza virus often proves to be resistant to currently available drugs, due single amino acid substitutions conferred by the mutations in the gene coding for neuraminidase protein. The latest Influenza A virus A/Perth/262/2009(H1N1) sequence with accession number ADJ67981 was selected from NCBI. The BLAST program was used to identify the best template structure, which was found to be 3NSS_A. Sequence alignment was carried out with the template and query sequence, the identity and similarity was found to be 81.9% and 82.6% respectively. Homology modeling was performed using Accelrys Discovery Studio 3.5 software, the model with the lowest energy was then assessed for stereochemical quality and side-chain environment. The PDF energy and DOPE score of the best modeled structure was 2090.1682 and -43752.3632 respectively. Further active site optimization of the modeled protein was performed by molecular dynamics. The key active site residues which are crucial for further docking studies were ascertained

    Submucosal Gland Myoepithelial Cells Are Reserve Stem Cells That Can Regenerate Mouse Tracheal Epithelium

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    The mouse trachea is thought to contain two distinct stem cell compartments that contribute to airway repair-basal cells in the surface airway epithelium (SAE) and an unknown submucosal gland (SMG) cell type. Whether a lineage relationship exists between these two stem cell compartments remains unclear. Using lineage tracing of glandular myoepithelial cells (MECs), we demonstrate that MECs can give rise to seven cell types of the SAE and SMGs following severe airway injury. MECs progressively adopted a basal cell phenotype on the SAE and established lasting progenitors capable of further regeneration following reinjury. MECs activate Wnt-regulated transcription factors (Lef-1/TCF7) following injury and Lef-1 induction in cultured MECs promoted transition to a basal cell phenotype. Surprisingly, dose-dependent MEC conditional activation of Lef-1 in vivo promoted self-limited airway regeneration in the absence of injury. Thus, modulating the Lef-1 transcriptional program in MEC-derived progenitors may have regenerative medicine applications for lung diseases

    DMSO and Betaine Greatly Improve Amplification of GC-Rich Constructs in De Novo Synthesis

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    In Synthetic Biology, de novo synthesis of GC-rich constructs poses a major challenge because of secondary structure formation and mispriming. While there are many web-based tools for codon optimizing difficult regions, no method currently exists that allows for potentially phenotypically important sequence conservation. Therefore, to overcome these limitations in researching GC-rich genes and their non-coding elements, we explored the use of DMSO and betaine in two conventional methods of assembly and amplification. For this study, we compared the polymerase (PCA) and ligase-based (LCR) methods for construction of two GC-rich gene fragments implicated in tumorigenesis, IGF2R and BRAF. Though we found no benefit in employing either DMSO or betaine during the assembly steps, both additives greatly improved target product specificity and yield during PCR amplification. Of the methods tested, LCR assembly proved far superior to PCA, generating a much more stable template to amplify from. We further report that DMSO and betaine are highly compatible with all other reaction components of gene synthesis and do not require any additional protocol modifications. Furthermore, we believe either additive will allow for the production of a wide variety of GC-rich gene constructs without the need for expensive and time-consuming sample extraction and purification prior to downstream application

    Horizontal Transfer of a Nitrate Assimilation Gene Cluster and Ecological Transitions in Fungi: A Phylogenetic Study

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    High affinity nitrate assimilation genes in fungi occur in a cluster (fHANT-AC) that can be coordinately regulated. The clustered genes include nrt2, which codes for a high affinity nitrate transporter; euknr, which codes for nitrate reductase; and NAD(P)H-nir, which codes for nitrite reductase. Homologs of genes in the fHANT-AC occur in other eukaryotes and prokaryotes, but they have only been found clustered in the oomycete Phytophthora (heterokonts). We performed independent and concatenated phylogenetic analyses of homologs of all three genes in the fHANT-AC. Phylogenetic analyses limited to fungal sequences suggest that the fHANT-AC has been transferred horizontally from a basidiomycete (mushrooms and smuts) to an ancestor of the ascomycetous mold Trichoderma reesei. Phylogenetic analyses of sequences from diverse eukaryotes and eubacteria, and cluster structure, are consistent with a hypothesis that the fHANT-AC was assembled in a lineage leading to the oomycetes and was subsequently transferred to the Dikarya (Ascomycota+Basidiomycota), which is a derived fungal clade that includes the vast majority of terrestrial fungi. We propose that the acquisition of high affinity nitrate assimilation contributed to the success of Dikarya on land by allowing exploitation of nitrate in aerobic soils, and the subsequent transfer of a complete assimilation cluster improved the fitness of T. reesei in a new niche. Horizontal transmission of this cluster of functionally integrated genes supports the “selfish operon” hypothesis for maintenance of gene clusters
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