109 research outputs found

    Equilibrium studies on sorption of an anionic dye onto acid activated water hyacinth roots

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    The inappropriate disposal of dyes in wastewater constitutes an environmental problem and can cause damage to the ecosystem. Present investigation deals with the utilization of water hyacinth roots (collected from the ponds) as adsorbent for the removal of anionic dye from its aqueous solutions. Batch studies were conducted to evaluate the adsorption capacity of the dye, Congo red on the sorbent with respect to the variations in initial pH, contact time and initial dye concentration and the adsorbent. The effective pH for better adsorption of Congo red on water hyacinth roots was found to be 6.0. Equilibrium was reached in about 3 h contact time. Equilibrium isotherms for the adsorption of Congo red on water hyacinth root were analyzed by the Freundlich, Langmuir and Redlich–Peterson isotherm equations. Results showed that Redlich–Peterson isotherm best-fits with the Congo red adsorption isotherm data on all initial dye concentrations. The Freundlich isotherm also showed comparable fit

    Kinetic Modeling and Effect of Process Parameters on Selenium Removal Using Strong Acid Resin

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    Heavy metal pollution due to the contamination of Selenium above the tolerable limit in the natural environment is a challenging issue that environmental scientists face. This study is aimed at identifying ion exchange technology as a feasible solution to remove selenium ions using 001x7 resin. Parametric experiments were conducted to identify the optimal pH, sorbent dose and speed of agitation. Selenium removal efficiency of 85% was attained at pH 5.0 with 100 mg/L selenium concentration. The increase in resin dose was found to increase removal efficiency. However, metal uptake decreased. The experiments on the effect of concentration proved the negative effect of higher concentrations of selenium on removal efficiency. The ion exchange process was proved to be optimal at an agitation speed of 200 rpm and a temperature of 35 °C. Pseudo second order model was found to fit the kinetic data very well compared to the pseudo-first order model and the pseudo second order rate constant was estimated as 8.725x10-5 g mg-1 min-1 with a solution containing 100 mg/L selenium

    OPTIMIZATION OF INULINASE PRODUCTION USING COPRA WASTE BY Kluyveromyces marxianus var. marxianus

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    Kluyveromyces marxianus var. marxianus was found to secrete a large amount of extracellular inulinase in to the medium. The optimization of inulinase pro¬duction using copra waste as a carbon source was performed with statistical methodology based on experimental designs. The screening of eighteen nut¬rients for their influence on inulinase production was achieved using a Plackett––Burman design. Corn steep liquor, (NH4)2SO4, ZnSO47H2O, K2HPO4 and urea were selected based on their positive influence on inulinase production. The selected components were optimized using response surface methodology (RSM). The optimum conditions are: corn steep liquor – 0.0560 (g/gds), (NH4)2SO4 – 0.0084 (g/gds), ZnSO47H2O – 0.0254 (g/gds), K2HPO4 – 0.0037 (g/gds) and urea - 0.02147 (g/gds). These conditions were validated experimentally which revealed an enhanced inulinase yield of 372 U/gds

    NANOCOMPOSITE APPLICATION FOR SELENIUM REMOVAL – PARAMETRIC STUDIES AND KINETIC MODELING

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    Nano composite material was synthesized using calcium hydroxy apatite and Phoenix Dactlyifera tree powder using wet chemical precipitation method and characterized using scanning electron microscopy and Fourier transform infrared spectroscopy. The influence of operating parameters namely initial pH (3 -11), selenium concentration (50 -200 mg L-1 ), nanocomposite dose (0.5 - 6.0 g L-1 ), presence of competitor chloride ion (0 -10 g L-1 ) and agitation speed (0 – 600 rpm) on the metal uptake was studied. A correlation relating nano composite dose and selenium uptake was proposed as selenium uptake = 202.3 (e-0.259* nanocomposite dose) he maximum uptake capacity of the nanocomposite was found to be 57.27 mg g-1 under optimal environmental conditions with an initial selenium concentration of 100 mg L-1 . Monolayer sorption mechanism, proposed by Langmuir isotherm, was found to apply for this process and the isotherm constants were determined. Modified Ritchie second order and pseudo second order models were fitted to the experimental data and pseudo second order model correlated well with rate constant of 1.5 x 10-3 g mg-1 min-1 and maximum uptake capacity of 70.92 mg g-1 at 32 °C with 100 mg L-1 initial metal concentration. Ritchie model rate constant was evaluated as 1.41×10-2 min-1 under similar process conditions

    CNS activity of Pokeweed Anti-viral Protein (PAP) in mice infected with Lymphocytic Choriomeningitis Virus (LCMV)

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    BACKGROUND: Others and we have previously described the potent in vivo and in vitro activity of the broad-spectrum antiviral agent PAP (Pokeweed antiviral protein) against a wide range of viruses. The purpose of the present study was to further elucidate the anti-viral spectrum of PAP by examining its effects on the survival of mice challenged with lymphocytic choriomeningitis virus (LCMV). METHODS: We examined the therapeutic effect of PAP in CBA mice inoculated with intracerebral injections of the WE54 strain of LCMV at a 1000 PFU dose level that is lethal to 100% of mice within 7–9 days. Mice were treated either with vehicle or PAP administered intraperitoneally 24 hours prior to, 1 hour prior to and 24 hours, 48 hours 72 hours and 96 hours after virus inoculation. RESULTS: PAP exhibits significant in vivo anti- LCMV activity in mice challenged intracerebrally with an otherwise invariably fatal dose of LCMV. At non-toxic dose levels, PAP significantly prolonged survival in the absence of the majority of disease-associated symptoms. The median survival time of PAP-treated mice was >21 days as opposed to 7 days median survival for the control (p = 0.0069). CONCLUSION: Our results presented herein provide unprecedented experimental evidence that PAP exhibits antiviral activity in the CNS of LCMV-infected mice

    Role of the Two Component Signal Transduction System CpxAR in Conferring Cefepime and Chloramphenicol Resistance in Klebsiella pneumoniae NTUH-K2044

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    Background: Klebsiella pneumoniae is a Gram-negative, non-motile, facultative anaerobe belonging to the Enterobacteriaceae family of the c-Proteobacteria class in the phylum Proteobacteria. Multidrug resistant K. pneumoniae have caused major therapeutic problems worldwide due to emergence of extended-spectrum b-lactamase producing strains. Twocomponent systems serve as a basic stimulus-response coupling mechanism to allow organisms to sense and respond to changes in many different environmental conditions including antibiotic stress. Principal Findings: In the present study, we investigated the role of an uncharacterized cpxAR operon in bacterial physiology and antimicrobial resistance by generating isogenic mutant (DcpxAR) deficient in the CpxA/CpxR component derived from the hyper mucoidal K1 strain K. pneumoniae NTUH-K2044. The behaviour of DcpxAR was determined under hostile conditions, reproducing stresses encountered in the gastrointestinal environment and deletion resulted in higher sensitivity to bile, osmotic and acid stresses. The DcpxAR was more susceptible to b-lactams and chloramphenicol than the wild-type strain, and complementation restored the altered phenotypes. The relative change in expression of acrB, acrD, eefB efflux genes were decreased in cpxAR mutant as evidenced by qRT-PCR. Comparison of outer membrane protein profiles indicated a conspicuous difference in the knock out background. Gel shift assays demonstrated direct binding of CpxR KP to promoter region of ompC KP in a concentration dependent manner

    A Framework of Building and Locational Characteristics Ranking for Purpose-built Offices in Malaysia

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    The development of purpose-built office market in Malaysia is primarily resolved by a supplydemand market. Since the office market in Malaysia has displayed significance improvement due to increasing level of competitiveness, many characteristics of purpose-built office have appeared and become prominent during the process of assessment. These characteristics were generally used as indicators in property valuation, building performance as well as office market appraisal. Based on these characteristics, property market participants can evaluate their property proficiently based on their requirements, especially in decision making during business planning, investment or property management. Technology growth and national policy also gave contribution factors on revealing newly characteristics of purpose-built office such as green building, intelligent building and sustainable development model. The purpose of this article is to identify suitable characteristics of purpose-built office that can be used in Malaysia. Integral to achieving this objective, exploration on purpose built office characteristics in a global and local context will be reconsidered. As a result, a building and locational framework of purpose-built office’s characteristics in Malaysia will be diagnosed and verified appropriately

    The KNee OsteoArthritis Prediction (KNOAP2020) challenge:An image analysis challenge to predict incident symptomatic radiographic knee osteoarthritis from MRI and X-ray images

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    Objectives: The KNee OsteoArthritis Prediction (KNOAP2020) challenge was organized to objectively compare methods for the prediction of incident symptomatic radiographic knee osteoarthritis within 78 months on a test set with blinded ground truth. Design: The challenge participants were free to use any available data sources to train their models. A test set of 423 knees from the Prevention of Knee Osteoarthritis in Overweight Females (PROOF) study consisting of magnetic resonance imaging (MRI) and X-ray image data along with clinical risk factors at baseline was made available to all challenge participants. The ground truth outcomes, i.e., which knees developed incident symptomatic radiographic knee osteoarthritis (according to the combined ACR criteria) within 78 months, were not provided to the participants. To assess the performance of the submitted models, we used the area under the receiver operating characteristic curve (ROCAUC) and balanced accuracy (BACC). Results: Seven teams submitted 23 entries in total. A majority of the algorithms were trained on data from the Osteoarthritis Initiative. The model with the highest ROCAUC (0.64 (95% confidence interval (CI): 0.57–0.70)) used deep learning to extract information from X-ray images combined with clinical variables. The model with the highest BACC (0.59 (95% CI: 0.52–0.65)) ensembled three different models that used automatically extracted X-ray and MRI features along with clinical variables. Conclusion: The KNOAP2020 challenge established a benchmark for predicting incident symptomatic radiographic knee osteoarthritis. Accurate prediction of incident symptomatic radiographic knee osteoarthritis is a complex and still unsolved problem requiring additional investigation.</p
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