71 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

    Survival of patients treated with intra-aortic balloon counterpulsation at a tertiary care center in Pakistan – patient characteristics and predictors of in-hospital mortality

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    BACKGROUND: Intra-aortic balloon counterpulsation (IABC) has an established role in the treatment of patients presenting with critical cardiac illnesses, including cardiogenic shock, refractory ischemia and for prophylaxis and treatment of complications of percutaneous coronary interventions (PCI). Patients requiring IABC represent a high-risk subset with an expected high mortality. There are virtually no data on usage patterns as well as outcomes of patients in the Indo-Pakistan subcontinent who require IABC. This is the first report on a sizeable experience with IABC from Pakistan. METHODS: Hospital charts of 95 patients (mean age 58.8 (± 10.4) years; 78.9% male) undergoing IABC between 2000–2002 were reviewed. Logistic regression was used to determine univariate and multivariate predictors of in-hospital mortality. RESULTS: The most frequent indications for IABC were cardiogenic shock (48.4%) and refractory ischemia (24.2%). Revascularization (surgical or PCI) was performed in 74 patients (77.9%). The overall in-hospital mortality rate was 34.7%. Univariate predictors of in-hospital mortality included (odds ratio [95% CI]) age (OR 1.06 [1.01–1.11] for every year increase in age); diabetes (OR 3.68 [1.51–8.92]) and cardiogenic shock at presentation (OR 4.85 [1.92–12.2]). Furthermore, prior CABG (OR 0.12 [0.04–0.34]), and in-hospital revascularization (OR 0.05 [0.01–0.189]) was protective against mortality. In the multivariate analysis, independent predictors of in-hospital mortality were age (OR 1.13 [1.05–1.22] for every year increase in age); diabetes (OR 6.35 [1.61–24.97]) and cardiogenic shock at presentation (OR 10.0 [2.33–42.95]). Again, revascularization during hospitalization (OR 0.02 [0.003–0.12]) conferred a protective effect. The overall complication rate was low (8.5%). CONCLUSIONS: Patients requiring IABC represent a high-risk group with substantial in-hospital mortality. Despite this high mortality, over two-thirds of patients do leave the hospital alive, suggesting that IABC is a feasible therapeutic device, even in a developing country

    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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J Clean Prod 184:815–825Braga AM, Silvestre JD, de Brito J (2017) Compared environmental and economic impact from cradle to gate of concrete with natural and recycled coarse aggregates. J Clean Prod 162:529–543Chen C, Habert G, Bouzidi Y, Jullien A, Ventura A (2010) LCA allocation procedure used as an incitative method for waste recycling: an application to mineral additions in concrete. Res Con Rec 54(12):1231–1240Chen Z, Gu H, Bergman RD, Liang S (2020) Comparative life-cycle assessment of a high-rise mass timber building with an equivalent reinforced concrete alternative using the Athena impact estimator for buildings. Sustainability (Switzerland) 12(11):4708Colangelo F, Cioffi R (2017) Mechanical properties and durability of mortar containing fine fraction of demolition wastes produced by selective demolition in South Italy. Comp Part B: Eng 115:43–50Colangelo F, Petrillo A, Cioffi R, Borrelli C, Forcina A (2018a) Life cycle assessment of recycled concretes: a case study in southern Italy. Sci Total Env 615:1506–1517Colangelo F, Forcina A, Farina I, Petrillo A (2018b) Life cycle assessment (LCA) of different kinds of concrete containing waste for sustainable construction. Buildings 8(5):70Colangelo F, Navarro TG, Petrillo A, Farina I, Cioffi R (2020) Life-cycle impact of concrete with recycled materials. 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    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

    Participative Leadership and Organizational Identification in SMEs in the MENA Region: Testing the Roles of CSR Perceptions and Pride in Membership

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    The aim of this research is to explore the process linking participative leadership to organizational identification. The study examines the relationship between participative leadership and internal CSR perceptions of employees and also investigates the role that pride in membership plays in the affiliation of CSR perceptions with organizational identification. By studying these relationships, the paper aspires to contemplate new presumed mediators in the association of participative leadership with organizational identification as well as determine a possible novel antecedent of employee CSR perceptions. Empirical evidence is provided from data that was collected through a survey distributed to employees working for small- and medium-sized enterprises in three countries in the Middle East and North Africa regions, particularly the United Arab Emirates, Lebanon, and Tunisia. Findings show that participative leadership leads to positive internal CSR perceptions of employees and that these CSR perceptions lead to pride in membership which, in turn, results in organizational identification. Implications of these findings are also discussed
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