2,071 research outputs found

    Larvicidal and Repellent efficacy of some of the weed plant extracts against Culex quinquefasciatus Say

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    The indiscriminate use of synthetic insecticides over years to control mosquitoes has caused an array of adversities to human beings as well as to nature and to a greater extent it has inflicted damages to the natural environment and disturbed ecological balances. Insecticides in plant origin play an important role in the interruption of the transmission of mosquito-borne diseases at the individual as well as at the community levels. The present study tested the larvicidal activity of methanolic extracts of four plants viz., Uvaria narum A. DC. (Annonaceae), Morinda pubescens Sm. (Rubiaceae), Caesalpinia pulcherrima (Linn.) Sw. (Leguminosae) and Leea indica (Burm. f.) Merr. (Vitaceae) and repellent activity of Uvaria narum against Culex quinquefasciatus Say. From the tested plants it is observed that methanolic extracts of U. narum possesses the highest larvicidal activity and ensure 100% protection. The findings of the present investigation revealed that the methanolic extracts of the selected plants have remarkable larvicidal activity against Cx. quinquefasciatus

    Response to autotomy in anesthetized freshwater crab, Paratelphusa hydrodromous (Herbst)

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    To extend the knowledge of amputation and induction of autotomy, the freshwater crab Paratelphusa hydrodromous (Herbst) was chosen as a model system. Amputation of different legs of Paratelphusa hydrodromous (Herbst) was done in two conditions; normal and anesthetized crab. Autotomy of the amputated legs under normal condition was induced autotomy within seconds (1.6 to 37 seconds). However, the amputation conducted in ice cold anesthetized crab showed delayed autotomy in a wide range of time from 10.2 ± 0.83 minutes (cheliped) to 114.8 ± 4.3 minutes (2nd walking leg). The observations suggest that ice cold anesthesia lowers the signaling of pain to the brain and delays autotomy, the voluntary mechanism to escape from the predator/pain or frightened force

    Quinalphos Induced Antioxidant Status and Histopathological Changes in the Gill of the Freshwater Fish, Oreochromis mossambicus

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    To extend the knowledge about quinalphos induced antioxidant status and its related changes on the histopathology of gills, the freshwater fish Oreochromis mossambicus was chosen as a model system. Quinalphos treatment (0.5ÎĽl/ L for 30 and 60 days) decreased the activities of antioxidant enzymes with concomitant increase in the production of malondialdehyde. Increased reactive oxygen species generation coincides with the increase in the protein carbonyl in the gills of the treated fishes. Histological observation in the gill of quinalphos treated animal for 60 days showed several alterations as hypertrophy of gill arches, lifting of lamellar epithelium, degeneration of gill filament and lamellar epithelium and vasodilation in the lamellar axis when compared to the control group. These observations suggest that chronic exposure to pesticide affect the respiratory oxidative potential of the freshwater fish and this could be possibly due to quinalphos induced oxidative stress in the gill

    When the vertex coloring of a graph is an edge coloring of its line graph - a rare coincidence

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    The 3-consecutive vertex coloring number psi(3c)(G) of a graph G is the maximum number of colors permitted in a coloring of the vertices of G such that the middle vertex of any path P-3 subset of G has the same color as one of the ends of that P-3. This coloring constraint exactly means that no P-3 subgraph of G is properly colored in the classical sense. The 3-consecutive edge coloring number psi(3c)'(G) is the maximum number of colors permitted in a coloring of the edges of G such that the middle edge of any sequence of three edges (in a path P-4 or cycle C-3) has the same color as one of the other two edges. For graphs G of minimum degree at least 2, denoting by L(G) the line graph of G, we prove that there is a bijection between the 3-consecutive vertex colorings of G and the 3-consecutive edge colorings of L(G), which keeps the number of colors unchanged, too. This implies that psi(3c)(G) = psi(3c)'(L(G)); i.e., the situation is just the opposite of what one would expect for first sight

    Top Quark Physics at the Tevatron

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    The discovery of the top quark in 1995, by the CDF and D0 collaborations at the Fermilab Tevatron, marked the dawn of a new era in particle physics. Since then, enormous efforts have been made to study the properties of this remarkable particle, especially its mass and production cross section. In this article, we review the status of top quark physics as studied by the two collaborations using the p-pbar collider data at sqrt(s) = 1.8 TeV. The combined measurement of the top quark mass, m_t = 173.8 +- 5.0 GeV/c^2, makes it known to a fractional precision better than any other quark mass. The production cross sections are measured as sigma (t-tbar) = 7.6 -1.5 +1.8 pb by CDF and sigma (t-tbar) = 5.5 +- 1.8 pb by D0. Further investigations of t-tbar decays and future prospects are briefly discussed.Comment: 119 pages, 59 figures, 17 tables Submitted to Int. J. Mod. Phys. A Fixed some minor error

    Larvicidal activities of 2-Aryl-2,3-Dihydroquinazolin -4-ones against malaria vector Anopheles arabiensis, In Silico ADMET prediction and molecular target investigation

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    Malaria, affecting all continents, remains one of the life-threatening diseases introduced by parasites that are transmitted to humans through the bites of infected Anopheles mosquitoes. Although insecticides are currently used to reduce malaria transmission, their safety concern for living systems, as well as the environment, is a growing problem. Therefore, the discovery of novel, less toxic, and environmentally safe molecules to effectively combat the control of these vectors is in high demand. In order to identify new potential larvicidal agents, a series of 2-aryl-1,2-dihydroquinazolin-4-one derivatives were synthesized and evaluated for their larvicidal activity against Anopheles arabiensis. The in silico absorption, distribution, metabolism, excretion, and toxicity (ADMET) properties of the compounds were also investigated and most of the derivatives possessed a favorable ADMET profile. Computational modeling studies of the title compounds demonstrated a favorable binding interaction against the acetylcholinesterase enzyme molecular target. Thus, 2-aryl-1,2-dihydroquinazolin-4-ones were identified as a novel class of Anopheles arabiensis insecticides which can be used as lead molecules for the further development of more potent and safer larvicidal agents for treating malaria.Fil: Venugopala, K. N.. Durban University Of Technology; SudáfricaFil: Pushpalatha, R.. Reva University; IndiaFil: Tratat, C.. King Faisal University; Arabia SauditaFil: Gleiser, Raquel M.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto Multidisciplinar de Biología Vegetal (P). Grupo Vinculado Centro de Relevamiento y Evaluación de Recursos Agrícolas y Naturales; ArgentinaFil: Bhandary, S.. Indian Institute Of Science Education And Research Bhopal; IndiaFil: Chopra, D.. Indian Institute Of Science Education And Research Bhopal; IndiaFil: Morsy, M.. King Faisal University; Arabia SauditaFil: Al-Dhubiab, B. E.. King Faisal University; Arabia SauditaFil: Attimarad, M. B.. King Faisal University; Arabia SauditaFil: Nair, A.. King Faisal University; Arabia SauditaFil: Sreeharsha, N.. King Faisal University; Arabia SauditaFil: Venugopala, R.. University Of Kwazulu-natal; SudáfricaFil: Deb, P. K.. Philadelphia University; JordaniaFil: Chandrashekharappa, S.. Institute For Stem Cell Biology And Regenerative Medicine; IndiaFil: Khalil, H.. King Faisal University; Arabia SauditaFil: Alwassil, O.. King Saud Bin Abdulaziz University For Health Sciences; Arabia SauditaFil: Abed, S. N.. Philadelphia University; JordaniaFil: Bataineh, Y. A.. Philadelphia University; JordaniaFil: Palenge, R.. Reva University; IndiaFil: Haroun, M.. King Faisal University; Arabia SauditaFil: Pottathil, S.. King Faisal University; Arabia SauditaFil: Girish, M. B.. Reva University; IndiaFil: Akrawi, S. H.. King Faisal University; Arabia SauditaFil: Mohanlall, V.. Durban University Of Technology; Sudáfric

    Biosurfactants produced by Bacillus subtilis A1 and Pseudomonas stutzeri NA3 reduce longevity and fecundity of Anopheles stephensi and show high toxicity against young instars

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    Anopheles stephensi acts as vector of Plasmodium parasites, which are responsible for malaria in tropical and subtropical areas worldwide. Currently, malaria management is a big challenge due to the presence of insecticide-resistant strains as well as to the development of Plasmodium species highly resistant to major antimalarial drugs. Therefore, the present study focused on biosurfactant produced by two bacteria Bacillus subtilis A1 and Pseudomonas stutzeri NA3, evaluating them for insecticidal applications against malaria mosquitoes. The produced biosurfactants were characterized using FT-IR spectroscopy and gas chromatography-mass spectrometry (GC-MS), which confirmed that biosurfactants had a lipopeptidic nature. Both biosurfactants were tested against larvae and pupae of A. stephensi. LC50 values were 3.58 (larva I), 4.92 (II), 5.73 (III), 7.10 (IV), and 7.99 (pupae) and 2.61 (I), 3.68 (II), 4.48 (III), 5.55 (IV), and 6.99 (pupa) for biosurfactants produced by B. subtilis A1 and P. stutzeri NA3, respectively. Treatments with bacterial surfactants led to various physiological changes including longer pupal duration, shorter adult oviposition period, and reduced longevity and fecundity. To the best of our knowledge, there are really limited reports on the mosquitocidal and physiological effects due to biosurfactant produced by bacterial strains. Overall, the toxic activity of these biosurfactant on all young instars of A. stephensi, as well as their major impact on adult longevity and fecundity, allows their further consideration for the development of insecticides in the fight against malaria mosquitoes

    Combined Forward-Backward Asymmetry Measurements in Top-Antitop Quark Production at the Tevatron

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    The CDF and D0 experiments at the Fermilab Tevatron have measured the asymmetry between yields of forward- and backward-produced top and antitop quarks based on their rapidity difference and the asymmetry between their decay leptons. These measurements use the full data sets collected in proton-antiproton collisions at a center-of-mass energy of s=1.96\sqrt s =1.96 TeV. We report the results of combinations of the inclusive asymmetries and their differential dependencies on relevant kinematic quantities. The combined inclusive asymmetry is AFBttˉ=0.128±0.025A_{\mathrm{FB}}^{t\bar{t}} = 0.128 \pm 0.025. The combined inclusive and differential asymmetries are consistent with recent standard model predictions
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