74 research outputs found

    STABILITY IMPROVEMENT OF IMMOBILIZED ALKALINE PHOSPHATASE USING CHITOSAN NANOPARTICLES

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    Abstract -Enzyme engineering via immobilization techniques is a suitable approach for improving enzyme function and stability and is superior to the other chemical or biological methods. In this study chitosan nanoparticles were synthesized using the Ionic Gelation method and were characterized by Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). Alkaline phosphatase was successfully immobilized on the chitosan nanoparticles in optimum conditions. Chitosan nanoparticles were used because of their special properties for enzyme immobilization. This study indicated that the immobilized enzyme has improved function at high temperature and during storage. Immobilization resulted in an increased range of optimum pH and temperature, and reusability of enzyme. Furthermore, the binding efficiency calculation indicated that the immobilized alkaline phosphatase conserved 71% of its native activity. Kinetic parameter studies indicated no significant difference between the immobilized and free enzymes

    Isolation and fine mapping of Rps6: An intermediate host resistance gene in barley to wheat stripe rust

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    A plant may be considered a nonhost of a pathogen if all known genotypes of a plant species are resistant to all known isolates of a pathogen species. However, if a small number of genotypes are susceptible to some known isolates of a pathogen species this plant maybe considered an intermediate host. Barley (Hordeum vulgare) is an intermediate host for Puccinia striiformis f. sp. tritici (Pst), the causal agent of wheat stripe rust. We wanted to understand the genetic architecture underlying resistance to Pst and to determine whether any overlap exists with resistance to the host pathogen, Puccinia striiformis f. sp. hordei (Psh). We mapped Pst resistance to chromosome 7H and show that host and intermediate host resistance is genetically uncoupled. Therefore, we designate this resistance locus Rps6. We used phenotypic and genotypic selection on F2:3 families to isolate Rps6 and fine mapped the locus to a 0.1 cM region. Anchoring of the Rps6 locus to the barley physical map placed the region on two adjacent fingerprinted contigs. Efforts are now underway to sequence the minimal tiling path and to delimit the physical region harbouring Rps6. This will facilitate additional marker development and permit identification of candidate genes in the region

    Preparation and characterization of cotton fabrics with antimicrobial properties through the application of chitosan/silver-zeolite film

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    The development of antimicrobial cotton fabrics using chitosan/silver-zeolite film has been investigated in the present work. The film was applied to 100% cotton fabric using a common pad-dry-cure technique and citric acid was used as crosslinking agent. The resulting fabrics were characterized through infrared spectroscopy (FTIR), contact angle and scanning electron microscopy with X-ray microanalysis (SEM/EDS). The antimicrobial activity of the fabrics was assessed through the viable-cell counting method and the materials showed activity against S. aureus and T. rubrum. The textile performance of the fabrics was analysed regarding their characteristics of hydrophilicity and breathability. The finishing did not change the hydrophilic behaviour of the material. Although the permeability to air has reduced 20%, the permeability to water vapour remained practically unchanged. Therefore, the results suggested that the process approach of applying chitosan/silver-zeolite film is recommended to produce textiles with antibacterial properties.CNPq-Brazil (Conselho Nacional de Desenvolvimento Científico e Tecnológico – Brazil/National Council of Scientific and Technological Development – Brazil) for the doctoral scholarship (233550/2014-3). This work is also financed by FEDER funds through the Competitivity Factors Operational Programme – COMPETE and by national funds through FCT – Foundation for Science and Technology within the scope of the project POCI-01-0145-FEDER-007136. This research was partially supported by the Strategic Funding UID/Multi/04423/2013 through national funds provided by FCT - Foundation for Science and Technology and European Regional Development Fund (ERDF), in the framework of the program PT2020.info:eu-repo/semantics/publishedVersio

    Knowledge of modifiable risk factors of heart disease among patients with acute myocardial infarction in Karachi, Pakistan: a cross sectional study

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    BACKGROUND: Knowledge is an important pre-requisite for implementing both primary as well as secondary preventive strategies for cardiovascular disease (CVD). There are no estimates of the level of knowledge of risk factor of heart disease in patients with CVD. We estimated the level of knowledge of modifiable risk factors and determined the factors associated with good level of knowledge among patients presenting with their first acute myocardial infarction (AMI) in a tertiary care hospital in Karachi, Pakistan. METHODS: A hospital based cross-sectional study was conducted at the National Institute of Cardiovascular Disease, a major tertiary care hospital in Karachi Pakistan. Patients admitted with their first AMI were eligible to participate. Standard questionnaire was used to interview 720 subjects. Knowledge of four modifiable risk factors of heart disease: fatty food consumption, smoking, obesity and exercise were assessed. The participants knowing three out of four risk factors were regarded as having a good level of knowledge. A multiple logistic regression model was constructed to identify the determinants of good level of knowledge. RESULTS: The mean age (SD) was 54 (11.66) years. A mere 42% of our study population had a good level of knowledge. In multiple logistic regression analysis, independent predictors of "good" level of knowledge were (odds ratio [95% confidence interval]) more than ten years of schooling were 2.5 [1.30, 4.80] (verses no schooling at all) and nuclear family system (verses extended family system) 2.54 [1.65, 3.89]. In addition, Sindhi ethnicity OR [3.03], higher level of exercise OR [2.76] and non user of tobacco OR [2.53] were also predictors of good level of knowledge. CONCLUSION: Our findings highlight the lack of good level of knowledge of modifiable risk factors for heart disease among subjects admitted with AMI in Pakistan. There is urgent need for aggressive and targeted educational strategies in the Pakistani population

    Differential gene expression in nearly isogenic lines with QTL for partial resistance to Puccinia hordei in barley

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    <p>Abstract</p> <p>Background</p> <p>The barley-<it>Puccinia hordei </it>(barley leaf rust) pathosystem is a model for investigating partial disease resistance in crop plants and genetic mapping of phenotypic resistance has identified several quantitative trait loci (QTL) for partial resistance. Reciprocal QTL-specific near-isogenic lines (QTL-NILs) have been developed that combine two QTL, <it>Rphq</it>2 and <it>Rphq</it>3, the largest effects detected in a recombinant-inbred-line (RIL) population derived from a cross between the super-susceptible line L94 and partially-resistant line Vada. The molecular mechanism underpinning partial resistance in these QTL-NILs is unknown.</p> <p>Results</p> <p>An Agilent custom microarray consisting of 15,000 probes derived from barley consensus EST sequences was used to investigate genome-wide and QTL-specific differential expression of genes 18 hours post-inoculation (hpi) with <it>Puccinia hordei</it>. A total of 1,410 genes were identified as being significantly differentially expressed across the genome, of which 55 were accounted for by the genetic differences defined by QTL-NILs at <it>Rphq</it>2 and <it>Rphq</it>3. These genes were predominantly located at the QTL regions and are, therefore, positional candidates. One gene, encoding the transcriptional repressor Ethylene-Responsive Element Binding Factor 4 (<it>HvERF4</it>) was located outside the QTL at 71 cM on chromosome 1H, within a previously detected eQTL hotspot for defence response. The results indicate that <it>Rphq</it>2 or <it>Rphq</it>3 contains a <it>trans</it>-eQTL that modulates expression of <it>HvERF4</it>. We speculate that HvERF4 functions as an intermediate that conveys the response signal from a gene(s) contained within <it>Rphq</it>2 or <it>Rphq</it>3 to a host of down-stream defense responsive genes. Our results also reveal that barley lines with extreme or intermediate partial resistance phenotypes exhibit a profound similarity in their spectrum of <it>Ph</it>-responsive genes and that hormone-related signalling pathways are actively involved in response to <it>Puccinia hordei</it>.</p> <p>Conclusions</p> <p>Differential gene expression between QTL-NILs identifies genes predominantly located within the target region(s) providing both transcriptional and positional candidate genes for the QTL. Genetically mapping the differentially expressed genes relative to the QTL has the potential to discover <it>trans</it>-eQTL mediated regulatory relays initiated from genes within the QTL regions.</p

    Comparative LCA of concrete with recycled aggregates: a circular economy mindset in Europe

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    [EN] Purpose Construction and demolition waste (C&DW) is the largest waste stream in the European Union (EU) and all over the world. Proper management of C&DW and recycled materials¿including the correct handling of hazardous waste¿can have major benefits in terms of sustainability and the quality of life. The Waste Framework Directive 2008/98/EC aims to have 70% of C&DW recycled by 2020. However, except for a few EU countries, only about 50% of C&DW is currently being recycled. In the present research, the environmental impact of concrete with recycled aggregates and with geopolymer mixtures is analysed. The aim of the present research is to propose a comparative LCA of concrete with recycled aggregates in the context of European politics. Methods Life cycle assessment (LCA) methodology is applied using Simapro© software. A cradle to grave analysis is carried out. The results are analysed based on the database Ecoinvent 3.3 and Impact 2002+. Results Results show that the concrete with 25% recycled aggregates is the best solution from an environmental point of view. Furthermore, geopolymer mixtures could be a valid alternative to reduce the phenomenon of ¿global warming¿; however, the production of sodium silicate and sodium hydroxide has a great environmental impact. Conclusions A possible future implementation of the present study is certainly to carry out an overall assessment and to determine the most cost-effective option among the different competing alternatives through the life cycle cost analysis.Colangelo, F.; Gómez-Navarro, T.; Farina, I.; Petrillo, A. (2020). Comparative LCA of concrete with recycled aggregates: a circular economy mindset in Europe. International Journal of Life Cycle Assessment. 25(9):1790-1804. https://doi.org/10.1007/s11367-020-01798-6S17901804259Akhtar A, Sarmah (2018) Construction and demolition waste generation and properties of recycled aggregate concrete: a global perspective. 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