66 research outputs found

    Qualitative and Quantitative Analysis of Clerodendron colebrookianum Walp. Leaves and Zingiber cassumunar Roxb. Rhizomes

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    This article describes simple methods for performing qualitative and quantitative analysis of Clerodendron colebrookianum leaves and Zingiber cassumunar rhizomes. The distribution of the main active principles (phlobatannins, flavonoids, alkaloids, saponins, tannins, terpenoids, steroids, glycosides and anthraquinones) in C. colebrookianum leaves and Z. cassumunar rhizomes were assessed. Both the plant materials were found to contain all the above components except for the absence of anthraquinones in both Z. cassumunar rhizomes and C. colebrookianum leaves, and absence of phlobatannin and glycosides in C. colebrookianum leaves. The importances of the distribution of these chemical constituents were discussed. This study provides scientific method to investigate the active components of the above mentioned plants

    Microwave-assisted in situ laser dye incorporation into high sensitivity whispering gallery mode microresonators

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    Optical whispering gallery mode microresonators (WGM-μRs) are powerful sensitive components with many analytical applications. Here, spherical WGM-μRs have been synthesised in a single-step microwave (MW)-assisted heterophase polymerisation. The microresonators are based on poly(styrene) beads into which the organic lasing dye nile red was incorporated as gain medium in situ during the polymerisation. The particle diameter and diameter distribution of the synthesised particles were tuned in the range of around 200 nm up to 50 μm by adjusting the concentration between stabiliser poly-(N-vinyl pyrrolidone) (PVP) and monomer styrene, and the solvent composition in the dispersion process. Lower water content enabled the synthesis of spherical particles with large size polydispersity, from which WGM-μRs with a variety of diameters were selected. Microspheres with diameters ≳3.5 μm supported WGMs. The WGMs were excited through free space via the fluorescence of the laser dye. Pumping power levels <1 μW were sufficient to excite WGMs. WGM shifts of beads with diameter between ≈5 and 30 μm measured in air and water show a sensitivity up to 54 nm/RIU for the smallest particles. Dye doped WGM-μR in the low μm size range obtained by the MW-assisted polymerisation process with its versatility, low processing times and high yields opens new horizons for the applications of these systems as sensors

    EXPANSIN A1-mediated radial swelling of pericycle cells positions anticlinal cell divisions during lateral root initiation

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    In plants, postembryonic formation of new organs helps shape the adult organism. This requires the tight regulation of when and where a new organ is formed and a coordination of the underlying cell divisions. To build a root system, new lateral roots are continuously developing, and this process requires the tight coordination of asymmetric cell division in adjacent pericycle cells. We identified EXPANSIN A1 (EXPA1) as a cell wall modifying enzyme controlling the divisions marking lateral root initiation. Loss of EXPA1 leads to defects in the first asymmetric pericycle cell divisions and the radial swelling of the pericycle during auxin-driven lateral root formation. We conclude that a localized radial expansion of adjacent pericycle cells is required to position the asymmetric cell divisions and generate a core of small daughter cells, which is a prerequisite for lateral root organogenesis

    Antioxidant, antibacterial, cytotoxic, and apoptotic activity of stem bark extracts of Cephalotaxus griffithii Hook. f

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    <p>Abstract</p> <p>Background</p> <p><it>Cephalotaxus </it>spp. are known to possess various therapeutic potentials. <it>Cephalotaxus griffithii</it>, however, has not been evaluated for its biological potential. The reason may be the remoteness and inaccessibility of the habitat where it is distributed. The main aim of this study was to: (1) evaluate multiple biological potentials of stem bark of <it>C. griffithii</it>, and (2) identify solvent extract of stem bark of <it>C. griffithii </it>to find the one with the highest specific biological activity.</p> <p>Methods</p> <p>Dried powder of stem bark of <it>C. griffithii </it>was exhaustively extracted serially by soaking in petroleum ether, acetone and methanol to fractionate the chemical constituents into individual fractions or extracts. The extracts were tested for total phenolic and flavonoid content, antioxidant (DPPH radical scavenging, superoxide radical scavenging, and reducing power models), antibacterial (disc diffusion assay on six bacterial strains), cytotoxic (MTT assay on HeLa cells), and apoptotic activity (fluorescence microscopy, DNA fragmentation assay, and flow cytometry on HeLa cells).</p> <p>Results</p> <p>Among the three extracts of stem bark of <it>C. griffithii</it>, the acetone extract contained the highest amount of total phenolics and flavonoids and showed maximum antioxidant, antibacterial, cytotoxic (IC<sub>50 </sub>of 35.5 ± 0.6 μg/ml; P < 0.05), and apoptotic (46.3 ± 3.6% sub-G0/G1 population; P < 0.05) activity, followed by the methanol and petroleum ether extracts. However, there was no significant difference observed in IC<sub>50 </sub>values (DPPH scavenging assay) of the acetone and methanol extracts and the positive control (ascorbic acid). In contrast, superoxide radical scavenging assay-based antioxidant activity (IC<sub>50</sub>) of the acetone and methanol extracts was significantly lower than the positive control (P < 0.05). Correlation analysis suggested that phenolic and flavonoid content present in stem bark of <it>C. griffithii </it>extracts was responsible for the high antioxidant, cytotoxic, and apoptotic activity (P < 0.05).</p> <p>Conclusions</p> <p>Stem bark of <it>C. griffithii </it>has multiple biological effects. These results call for further chemical characterization of acetone extract of stem bark of <it>C. griffithii </it>for specific bioactivity.</p

    Laparoscopic versus conventional appendectomy - a meta-analysis of randomized controlled trials

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    <p>Abstract</p> <p>Background</p> <p>Although laparoscopic surgery has been available for a long time and laparoscopic cholecystectomy has been performed universally, it is still not clear whether open appendectomy (OA) or laparoscopic appendectomy (LA) is the most appropriate surgical approach to acute appendicitis. The purpose of this work is to compare the therapeutic effects and safety of laparoscopic and conventional "open" appendectomy by means of a meta-analysis.</p> <p>Methods</p> <p>A meta-analysis was performed of all randomized controlled trials published in English that compared LA and OA in adults and children between 1990 and 2009. Calculations were made of the effect sizes of: operating time, postoperative length of hospital stay, postoperative pain, return to normal activity, resumption of diet, complications rates, and conversion to open surgery. The effect sizes were then pooled by a fixed or random-effects model.</p> <p>Results</p> <p>Forty-four randomized controlled trials with 5292 patients were included in the meta-analysis. Operating time was 12.35 min longer for LA (95% CI: 7.99 to 16.72, p < 0.00001). Hospital stay after LA was 0.60 days shorter (95% CI: -0.85 to -0.36, p < 0.00001). Patients returned to their normal activity 4.52 days earlier after LA (95% CI: -5.95 to -3.10, p < 0.00001), and resumed their diet 0.34 days earlier(95% CI: -0.46 to -0.21, p < 0.00001). Pain after LA on the first postoperative day was significantly less (p = 0.008). The overall conversion rate from LA to OA was 9.51%. With regard to the rate of complications, wound infection after LA was definitely reduced (OR = 0.45, 95% CI: 0.34 to 0.59, p < 0.00001), while postoperative ileus was not significantly reduced(OR = 0.91, 95% CI: 0.57 to 1.47, p = 0.71). However, intra-abdominal abscess (IAA), intraoperative bleeding and urinary tract infection (UIT) after LA, occurred slightly more frequently(OR = 1.56, 95% CI: 1.01 to 2.43, p = 0.05; OR = 1.56, 95% CI: 0.54 to 4.48, p = 0.41; OR = 1.76, 95% CI: 0.58 to 5.29, p = 0.32).</p> <p>Conclusion</p> <p>LA provides considerable benefits over OA, including a shorter length of hospital stay, less postoperative pain, earlier postoperative recovery, and a lower complication rate. Furthermore, over the study period it was obvious that there had been a trend toward fewer differences in operating time for the two procedures. Although LA was associated with a slight increase in the incidence of IAA, intraoperative bleeding and UIT, it is a safe procedure. It may be that the widespread use of LA is due to its better therapeutic effect.</p

    Full Color Camouflage in a Printable Photonic Blue-Colored Polymer

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    A blue reflective photonic polymer coating which can be patterned in full color, from blue to red, by printing with an aqueous calcium nitrate solution has been fabricated. Color change in the cholesteric liquid-crystalline polymer network over the entire visible spectrum is obtained by the use of nonreactive mesogen. The pattern in the coating is hidden in the blue color dry state and appears upon exposure to water or by exhaling breath onto it due to different degrees of swelling of the polymer network. The degree of swelling depends on the printed amount of calcium which acts as a cross-linker. The printed full color pattern can also be hidden simply by using a circular polarizer. The responsive full color camouflage polymers are interesting for various applications ranging from responsive house and automobile decors to anticounterfeit labels and data encryption

    Robust protective relay setting and coordination using modified differential evolution considering different network topologies

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    10.1007/978-3-319-03756-1_10Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)8298 LNCSPART 2107-11

    Voltage Stability Assessment by Holomorphically Estimating the Bifurcation Point of Electric Grids

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    Modernization of the grid, inclusive of high renewable energy penetration and the consequent power variability, requires fast power-flow computations for useful management of power in new network configurations. Voltage stability of an electrical grid is a big challenge to solve in power system operation, so as to avoid voltage collapse and subsequent black outs. This paper presents a novel means of voltage stability assessment by estimating the bifurcation point within the context of a non-iterative power-flow method known as Holomorphic Embedded Power Flow (HEPF). HEPF is computationally fast and guarantees solution to the power flow problem through constructing the mathematical solution for the power-flow problem, provided the solution exists. A 3-bus system is first used to explain the holomorphic matrix formulations and then demonstrated on a 4-bus system and a 9-bus test-case to evaluate proximity to a critical point with respect to load change
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