1,706 research outputs found

    Electrokinetic Enhanced Bioremediation of Soils Contaminated with Petroleum Hydrocarbons

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    Desorption of phenanthrene resulting from hydraulic flow is compared to desorption driven by electroosmotic flow with a similar flow rate. The power required for the hydraulic flow test was compared with the consumed power in the electrokinetics test. A novel approach, anode-cathode-compartment (ACC), was proposed to stabilize pH and distribute nutrients in soil in order to enhance electrokinetic bioremediation of soil contaminated with biodegradable compounds. The ACC technique was applied to investigate electrokinetic bioremediation of soil contaminated with phenanthrene. Mycobacterium pallens sp. was used to degrade phenanthrene. Solar energy was used to generate power for the hybrid technique. Three distinct bacterial strains designated as AC16, SM155, and SB53, were subjected to investigation, including ability to grow in liquid medium at different diesel fuel concentrations, identifying functional genes, and the ability to grow at different temperatures and pH. Electrokinetic bioremediation with ACC technique was conducted to mitigate soil contaminated with diesel fuel. The tests were conducted using the novel bacterial strains AC16, SM155 and SB53. The results showed that, the phenanthrene concentration in effluent samples after desorption by electroosmotic flow was found to be three to four times the concentration after desorption by hydraulic flow. The new ACC technique overcomes the shortcomings of other pH stabilization techniques by stabilizing the pH without the need for pumping or amendments. The use of solar panels as a sole source of power can reduce electricity transmission expenses and eliminate power loss in transmission lines. Diesel degradation in tests conducted with electrokinetic bioremediation was between 20 and 30%

    Space Vector Pulse Width Modulation Technique Applied to Two Level Voltage Source Inverter

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    Space vector pulse width modulation SVPWM provides a better technique compared to the other pulse width modulation techniques. This paper presents simulation and implementation of SVPWM signal generation for driving three phase two level voltage source inverter VSI, also proposes and analyzes a new switching sequence for generating an SVPWM. Simulation results are obtained using the simulation package PSIM. and the inverter performance is evaluated in terms of total harmonic distortion (THD). The model is experimentally implemented and verified on Arduino Mega Atmega2560 microcontroller

    A Brief Comparison of K-means and Agglomerative Hierarchical Clustering Algorithms on Small Datasets

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    In this work, the agglomerative hierarchical clustering and K-means clustering algorithms are implemented on small datasets. Considering that the selection of the similarity measure is a vital factor in data clustering, two measures are used in this study - cosine similarity measure and Euclidean distance - along with two evaluation metrics - entropy and purity - to assess the clustering quality. The datasets used in this work are taken from UCI machine learning depository. The experimental results indicate that k-means clustering outperformed hierarchical clustering in terms of entropy and purity using cosine similarity measure. However, hierarchical clustering outperformed k-means clustering using Euclidean distance. It is noted that performance of clustering algorithm is highly dependent on the similarity measure. Moreover, as the number of clusters gets reasonably increased, the clustering algorithms’ performance gets higher

    Phytochemical Investigation and B Ioactivity Screening of Vitex (Verbenaceae) and Ficus (Moraceae) Species

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    The study on Vitex longisepala involves extraction, various chromatographic methods and structural determination by spectroscopic techniques such as IR, compounds were also elucidated by comparison with the previous works. works on leaves and bark of the plant yielded cholesterol (51),para-hydroxybenzoic acid (52), terpene. Crude extracts and isolated compounds from two parts of this plant were screened for antimicrobial activity using disc diffusion method and cytotoxic activity by using microtitration method. compouds exhibited antimicrobial activity against Gram-possitive and Gram-negative bacteria Cholesterol exhibited significant cytotoxic activity against T-lymphoblastic leukemic cell line with IC₅₀ 10 µg/ml. not show any antimicrobial activity against fungi. The methanol crude extract of the bark failed to show any significant antimicrobial activity, while the petroleum ether and the chloroform crude extracts of the bark exhibited weak antimicrobial activity against Bacillus cereus. The study on Vitex quinata involved the same procedure adopted above. Isolation works on the leaves and bark of the plant yielded cholesterol (51), 13- sitosterol (57), para-hydroxybenzoic acid (52), fructose (53), glucose (58), catechin (55), quercetin (59) and quercitrin (60). However, the bark of the plant yielded a mixture of long-chain compound, fatty acid and unidentified terpene. The crude extracts and isolated compounds of this plant were tested for antimicrobial and cytotoxic activity using disc diffusion and microtitration methods respectively. The crude extracts and pure isolated compounds exhibited positive antimicrobial results against two bacteria organisms and negative results against four fungi. Cholesterol and β-sitosterol gave cytotoxic activity against T -lymphoblastic leukemic cell line with IC₅₀ 10 and 25 µg/ml respectively. Detail investigation on the leaves, bark and fruits of Ficus benjamina has resulted in the isolation of seven compounds. The structure of these compounds were elucidated by means of spectroscopic methods including by the extensive use of various NMR techniques and also comparison with previous studies. The use of High Field NMR is essential in structural determination of these complex molecules. With the aids of various NMR experimental techniques and oth er spectroscopic methods such as IR, UV and MS, the correct structures of the pure isolated compounds were established. (63), The presence of bioactive compounds in th is plant was detected by the use of antimicrobial organism. crude plant extracts or pure isolated compounds could be determined. of chloroform and methanol extracts of the leaves of Ficus benjamina gave no significant activity while caffeic acid gave IC₅₀ value of 25 µg/ml. Phytochemical studies on leaves and bark of Ficus elastica have resulted in the isolation of emodin (66), (70) together with long-chain fatty acids. were established based on spectral studies using different spectroscopic methods and on comparison with published data

    THE POTENT AND SELECTIVE HISTAMINE H3 RECEPTOR ANTAGONIST E169 ALLEVIATES COGNITIVE DEFICITS AND MITIGATES DISTURBED PI3K/AKT/GSK-3β SIGNALING PATHWAY IN MK801-INDUCED AMNESIA IN MICE

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    The role of Histamine H3 Receptors (H3Rs) in memory and the prospective of H3R antagonists in pharmacological control of neurodegenerative disorders, e.g., Alzheimer’s Disease (AD) is well-accepted. Therefore, the procognitive effects of acute systemic administration of H3R antagonist E169 (2.5-10 mg/kg, i.p.) on MK801- induced amnesia using the Novel Object Recognition Test (NORT) paradigm in C57BL/6J mice were evaluated. E169 (5 mg) provided a significant memory-improving effect on MK801-induced short- and long-term memory impairments in NORT. The E169 (5 mg) provided effects were comparable to those observed with the Phosphatidyl Inositol 3-Kinase (PI3K) inhibitor LY294002 and were abrogated with the H3R Agonist (R)-α-Methyl Histamine (RAMH). Also, results demonstrated that E169 ameliorated MK801-induced memory deficits by antagonism of H3Rs and by modulation of the disturbing levels of PI3K, Akt and GSK-3β expressed proteins, signifying that E169 mitigated the Akt-mTOR signaling pathway in the hippocampus of tested mice. Moreover, the results observed revealed that E169 (2.5-10 mg/kg, i.p.) did not alter anxiety levels and locomotor activity of animals in open field test demonstrating that performances improved following acute systemic administration with E169 in NORT are unrelated to changes in emotional responding or in spontaneous locomotor activity. In summary, these obtained results suggest the potential of H3R antagonists in simultaneously modulating disturbed brain neurotransmitters and imbalanced Akt-mTOR signaling pathway related to neurodegenerative disorders, e.g., AD

    Quercetin from methanol extracts of the leaves of Ficus benghalensis

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    Flavonoids are ubiquitous in photosynthesising cells and are commonly found in fruit, vegetables, nuts, seeds, stems, flowers, tea, wine, propolis and honey. For centuries, preparations containing these compounds as the principal physiologically active constituents have been used to treat human diseases. Increasingly, this class of natural products is becoming the subject of anti-infective research and many groups have isolated and identified the structures of flavonoids. In this study we concerned on determination flavonoids content from methanolic extracts of Ficus benghalensis using catechol and quercetin as standard. The result shows high content of quercetin in methanolic extracts.&nbsp

    A taxonomy of testimonial smothering

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    Kristie Dotson formulates testimonial smothering as a form of testimonial oppression where a speaker truncates or removes the content of her testimony leaving the testimony empty from any content for which the hearers demonstrated testimonial incompetence. On Dotson’s account of smothering, the speaker empties her testimony from all content relevant to the domain of exchange. However, Dotson’s account does not include or cover instances where a speaker smothers her testimony, yet her smothered testimony contains some content relevant to the domain of exchange. In this thesis, I present a more detailed analysis of testimonial smothering to showcase different ways in which oppressed speakers interact in exchanges in which they are oppressed. I take Dotson’s notion of smothering to be one form of testimonial smothering, which I call smothering via emptying. I introduce two other types of smothering, smothering via altering and smothering via echoing, to encompass cases where a speaker’s smothered testimony is not empty from content relevant to the domain of exchange. Then I use the taxonomy of testimonial smothering to showcase ways in which oppressed speakers can contribute to conversations in which they are oppressed.https://www.ester.ee/record=b550775
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