407 research outputs found

    Electrocoagulation removal of anthraquinone dye Alizarin Red S from aqueous solution using aluminum electrodes: kinetics, isothermal and thermodynamics studies

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    Electrocoagulation (EC) was used for the removal of anthraquinone dye, Alizarin Red S (ARS) from aqueous solution. The process was carried out in a batch electrochemical cell with Al electrodes in a monopolar connection. The effects of some important parameters such as current density, pH, temperature and initial dye concentration, on the process were investigated. Equilibrium was attained after 10 minutes at 30 °C. Pseudo-first order, pseudo-second order, Elovic, and Avrami kinetic models were used to test the experimental data in order to elucidate the kinetics of the electrocoagulation process; pseudo-first order and Avrami models best fitted the data. Experimental data were analyzed using six isotherm models: Langmuir, Freudlinch, Redlich–Peterson, Temkin, Dubinin–Radushkevich and Sips isotherms and it was found that the data fitted well with Dubinin–Radushkevich and Sips isotherm model. The study showed that the process depended on the current density, temperature, pH and initial dye concentration. The calculated thermodynamics parameters (ΔGo, ΔHo and ΔSo) indicated that the process is spontaneous and endothermic in nature

    Female genital tuberculosis – still a common cause of primary amenorrhea in developing countries

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    Primary amenorrhea is defined as, no menses by age 14yrs in absence of growth or development of secondary sexual characteristics and no menses by age 16yrs regardless of the presence of normal growth or development of secondary sexual characteristics. Although pulmonary tuberculosis remains the commonest and the most infectious type of tuberculosis, extra pulmonary tuberculosis is becoming more prevalent especially in young women throughout the world. We report a case of young woman presenting as primary amenorrhea apparently having no signs and symptoms of tuberculosis. 20 yrs old unmarried girl was referred for primary amenorrhea with normal secondary sexual characters and presence of uterus, tubes and ovaries on abdominal scan. Hormonal assay and karyotyping was normal. She had negative progesterone challenge test and estrogen progesterone challenge test. Diagnosis of genital tuberculosis was confirmed by diagnostic hysterolaparoscopy and positive tubercular polymerase chain reaction and culture.  Hysterolaparoscopy is a key tool for confirmation of diagnosis in cases of primary amenorrhea when the dilemma exists

    Abnormal Complement Activation and Inflammation in the Pathogenesis of Retinopathy of Prematurity

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    Retinopathy of prematurity (ROP) is a neurovascular complication in preterm babies, leading to severe visual impairment, but the underlying mechanisms are yet unclear. The present study aimed at unraveling the molecular mechanisms underlying the pathogenesis of ROP. A comprehensive screening of candidate genes in preterms with ROP (n = 189) and no-ROP (n = 167) was undertaken to identify variants conferring disease susceptibility. Allele and genotype frequencies, linkage disequilibrium and haplotypes were analyzed to identify the ROP-associated variants. Variants in CFH (p = 2.94 x 10(-7)), CFB (p = 1.71 x 10(-5)), FBLN5 (p = 9.2 x 10(-4)), CETP (p = 2.99 x 10(-5)), and CXCR4 (p = 1.32 x 10(-8)) genes exhibited significant associations with ROP. Further, a quantitative assessment of 27 candidate proteins and cytokines in the vitreous and tear samples of babies with severe ROP (n = 30) and congenital cataract (n = 30) was undertaken by multiplex bead arrays and further validated by western blotting and zymography. Significant elevation and activation of MMP9 (p = 0.038), CFH (p = 2.24 x 10(-5)), C3 (p = 0.05), C4 (p = 0.001), IL-1ra (p = 0.0019), vascular endothelial growth factor (VEGF) (p = 0.0027), and G-CSF (p = 0.0099) proteins were observed in the vitreous of ROP babies suggesting an increased inflammation under hypoxic condition. Along with inflammatory markers, activated macrophage/microglia were also detected in the vitreous of ROP babies that secreted complement component C3, VEGF, IL-1ra, and MMP-9 under hypoxic stress in a cell culture model. Increased expression of the inflammatory markers like the IL-1ra (p = 0.014), MMP2 (p = 0.0085), and MMP-9 (p = 0.03) in the tears of babies at different stages of ROP further demonstrated their potential role in disease progression. Based on these findings, we conclude that increased complement activation in the retina/vitreous in turn activated microglia leading to increased inflammation. A quantitative assessment of inflammatory markers in tears could help in early prediction of ROP progression and facilitate effective management of the disease, thereby preventing visual impairment

    Functional enrichment by direct plasmid recovery after Fluorescence Activated Cell Sorting

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    Iterative screening of expressed protein libraries using fluorescence-activated cell sorting (FACS) typically involves culturing the pooled clones after each sort. In these experiments, if cell viability is compromised by the sort conditions and/or expression of the target protein(s), rescue PCR provides an alternative to culturing but requires re-cloning and can introduce amplification bias. We haveoptimized a simple protocol using commercially available reagents to directly recover plasmid DNA from sorted cells for subsequenttransformation. We tested our protocol with 2 different screening systems in which 60% of the sorted cell population was recovered

    Single-cell characterization of autotransporter mediated Escherichia coli surface display of disulfide-bond containing proteins

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    Autotransporters (ATs) are a family of bacterial proteins containing a C-terminal ?-barrel-forming domain that facilitates the translocation of N-terminal passenger domain whose functions range from adhesion to proteolysis. Genetic replacement of the native passenger domain with heterologous proteins is an attractive strategy not only for applications such as biocatalysis, live-cell vaccines, and protein engineering but also for gaining mechanistic insights toward understanding AT translocation. The ability of ATs to efficiently display functional recombinant proteins containing multiple disulfides has remained largely controversial. By employing high-throughput single-cell flow cytometry, we have systematically investigated the ability of the Escherichia coli AT Antigen 43 (Ag43) to display two different recombinant reporter proteins, a single-chain antibody (M18 scFv) that contains two disulfides and chymotrypsin that contains four disulfides, by varying the signal peptide and deleting the different domains of the native protein. Our results indicate that only the C-terminal ?-barrel and the threaded ?-helix are essential for efficient surface display of functional recombinant proteins containing multiple disulfides. These results imply that there are no inherent constraints for functional translocation and display of disulfide bond-containing proteins mediated by the AT system and should open new avenues for protein display and engineering

    Using LES to Study Reacting Flows and Instabilities in Annular Combustion Chambers

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    Great prominence is put on the design of aeronautical gas turbines due to increasingly stringent regulations and the need to tackle rising fuel prices. This drive towards innovation has resulted sometimes in new concepts being prone to combustion instabilities. In the particular field of annular combustion chambers, these instabilities often take the form of azimuthal modes. To predict these modes, one must compute the full combustion chamber, which remained out of reach until very recently and the development of massively parallel computers. Since one of the most limiting factors in performing Large Eddy Simulation (LES) of real combustors is estimating the adequate grid, the effects of mesh resolution are investigated by computing full annular LES of a realistic helicopter combustion chamber on three grids, respectively made of 38, 93 and 336 million elements. Results are compared in terms of mean and fluctuating fields. LES captures self-established azimuthal modes. The presence and structure of the modes is discussed. This study therefore highlights the potential of LES for studying combustion instabilities in annular gas turbine combustors

    Implications of Autonomy for the Expressiveness of Policy Routing

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    The Utilization of Data Analysis Techniques in Predicting Student Performance in Massive Open Online Courses (MOOCs)

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    The growth of the Internet has enabled the popularity of open online learning platforms to increase over the years. This has led to the inception of Massive Open Online Courses (MOOCs) that enrol, millions of people, from all over the world. Such courses operate under the concept of open learning, where content does not have to be delivered via standard mechanisms that institutions employ, such as physically attending lectures. Instead learning occurs online via recorded lecture material and online tasks. This shift has allowed more people to gain access to education, regardless of their learning background. However, despite these advancements in delivering education, completion rates for MOOCs are low. In order to investigate this issue, the paper explores the impact that technology has on open learning and identifies how data about student performance can be captured to predict trend so that at risk students can be identified before they drop-out. In achieving this, subjects surrounding student engagement and performance in MOOCs and data analysis techniques are explored to investigate how technology can be used to address this issue. The paper is then concluded with our approach of predicting behaviour and a case study of the eRegister system, which has been developed to capture and analyse data. Keywords: Open Learning; Prediction; Data Mining; Educational Systems; Massive Open Online Course; Data Analysi
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