56 research outputs found

    A thorough Investigation of Rare-Earth Dy<sup>3+</sup> Substituted Cobalt-Chromium Ferrite and Its Magnetoelectric Nanocomposite

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    The stoichiometric compositions of a ferrite system with a chemical formula CoCr0.5DyxFe1.5−xO4 where x = 0.0, 0.025, 0.05, 0.075 and 0.1 were prepared by the sol-gel auto-combustion method. The structural, morphological and magnetic properties were studied by the X-ray diffraction (XRD), infra-red spectroscopy (IR), scanning electron microscopy, transmission electron microscopy and vibrating sample magnetometer. XRD analysis confirmed the cubic spinel structure of the prepared samples without the presence of any impurity and secondary phases. Selected area electron diffraction and IR measurements gives further confirmation to the XRD observations. Considering that strain mechanism, elastic properties and cation distribution play a major role for controlling the magnetic properties and therefore these properties were precisely evaluated through reliable methodologies such as XRD and IR data. The cation distribution was determined by the X-ray diffraction data which are further supported by the magnetization studies. Magnetoelectric properties of CoCr0.5DyxFe1.5−xO4 + BaTiO3 have also been investigated. The mechanisms involved are discussed in the manuscript

    Experimental Microbial Evolution of Extremophiles

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    Experimental microbial evolutions (EME) involves studying closely a microbial population after it has been through a large number of generations under controlled conditions (Kussell 2013). Adaptive laboratory evolution (ALE) selects for fitness under experimentally imposed conditions (Bennett and Hughes 2009; Dragosits and Mattanovich 2013). However, experimental evolution studies focusing on the contributions of genetic drift and natural mutation rates to evolution are conducted under non-selective conditions to avoid changes imposed by selection (HindrĂ© et al. 2012). To understand the application of experimental evolutionary methods to extremophiles it is essential to consider the recent growth in this field over the last decade using model non-extremophilic microorganisms. This growth reflects both a greater appreciation of the power of experimental evolution for testing evolutionary hypotheses and, especially recently, the new power of genomic methods for analyzing changes in experimentally evolved lineages. Since many crucial processes are driven by microorganisms in nature, it is essential to understand and appreciate how microbial communities function, particularly with relevance to selection. However, many theories developed to understand microbial ecological patterns focus on the distribution and the structure of diversity within a microbial population comprised of single species (Prosser et al. 2007). Therefore an understanding of the concept of species is needed. A common definition of species using a genetic concept is a group of interbreeding individuals that is isolated from other such groups by barriers of recombination (Prosser et al. 2007). An alternative ecological species concept defines a species as set of individuals that can be considered identical in all relevant ecological traits (Cohan 2001). This is particularly important because of the abundance and deep phylogenetic complexity of microbial communities. Cohan postulated that “bacteria occupy discrete niches and that periodic selection will purge genetic variation within each niche without preventing divergence between the inhabitants of different niches”. The importance of gene exchange mechanisms likely in bacteria and archaea and therefore extremophiles, arises from the fact that their genomes are divided into two distinct parts, the core genome and the accessory genome (Cohan 2001). The core genome consists of genes that are crucial for the functioning of an organism and the accessory genome consists of genes that are capable of adapting to the changing ecosystem through gain and loss of function. Strains that belong to the same species can differ in the composition of accessory genes and therefore their capability to adapt to changing ecosystems (Cohan 2001; Tettelin et al. 2005; Gill et al. 2005). Additional ecological diversity exists in plasmids, transposons and pathogenicity islands as they can be easily shared in a favorable environment but still be absent in the same species found elsewhere (Wertz et al. 2003). This poses a major challenge for studying ALE and community microbial ecology indicating a continued need to develop a fitting theory that connects the fluid nature of microbial communities to their ecology (Wertz et al. 2003; Coleman et al. 2006). Understanding the nature and contribution of different processes that determine the frequencies of genes in any population is the biggest concern in population and evolutionary genetics (Prosser et al. 2007) and it is critical for an understanding of experimental evolution

    Temporal Changes in Comorbidity Burden in Patients Having Percutaneous Coronary Intervention and Impact on Prognosis

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    This study aims to evaluate the impact of comorbidity burden on outcomes among patients who undergo percutaneous coronary intervention (PCI). We used the Nationwide Inpatient Sample to identify all PCI procedures undertaken in the United States between 2004 – 2014. We then determined comorbidity burden for each patient record based on the Charlson Comorbidity Score. Multivariable logistic regression models were used to examine the association between comorbidity burden and in-hospital mortality other in-hospital complications. A total of 6,601,526 PCI procedures were included in the analysis. Overall comorbidity burden increased over time, with severe comorbidity burden (defined as a CCI score ≄3) increasing from 5.3% in 2004 to 14.2% in 2014 (P<0.0001). After adjustment for confounding factors increasing comorbidity burden was independently associated with increased odds of in-hospital mortality, complications, length of hospital stay and total cost of hospitalisation post PCI. A CCI score of 1 was independently associated with an increase in the odds of in hospital mortality (OR 1.19 (95% CI 1.15-1.25)), a score of 2 associated with an almost 1.5-fold increase (OR 1.41 (95% CI 1.34-1.48)) and a score of ≄3 a 2-fold increase (OR 1.96 (95% CI 1.86-2.07)) compared to no comorbid burden (CCI score of 0). In conclusion, our results show that comorbid burden is independently associated with increased risk of in-hospital mortality, in-hospital complications, length of stay and healthcare costs
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