10,729 research outputs found

    MEMS On/off and x2 Optical Switch with Integrated Fiber Alignment Capability

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    An on/off free space optical switch is described in this paper. The device consists of intersecting cantilevers and is electrostatically actuated. A fiber is put onto the cantilevers and by controlling the position of the flber through actuation, switching operation can be achieved. The device is also suitable for inpackage fiber alignment application, where the cantilevers can be used as passive or active fiber alignment microstructure

    Chemical and biological investigations of Delonix regia (Bojer ex Hook.) Raf.

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    U radu je opisana izolacija pet sastojaka petroleterske i diklormetanske frakcije metanolnog ekstrakta kore biljke Delonix regia: lupeol (1), epilupeol (2), β-sitosterol (3), stigmasterol (4) i p-metoksibenzaldehid (5). Nadalje, testirano je antimikrobno djelovanje različitih ekstrakata difuzijskom metodom na disku (15 μg mm2). Zone inhibicije za sastojke topljive u petroleteru, tetraklormetanu i diklormetanu bile su 914 mm, 1113 mm, odnosno 920 mm, dok je zona inhibicije standarda kanamicina bila 2025 mm. U biološkom pokusu smrtnosti morskih kozica najveću toksičnost pokazali su spojevi topljivi u tetraklormetanu (LC50 = 0,83 μg mL1), dok je topljivost sastojaka topljivih u petroleteru i diklormetanu bila LC50 14,94, odnosno 3,29 μg mL1, a standarda vinkristin sulfata 0,812 μg mL1. Ovo je prvo izvješće o izolaciji sastojaka, antimikrobnom djelovanju i citotoksičnosti biljke D. regia.In this study five compounds, lupeol (1), epilupeol (2), β-sitosterol (3), stigmasterol (4) and p-methoxybenzaldehyde (5) were isolated from the petroleum ether and dichloromethane fractions of a methanolic extract of the stem bark of Delonix regia. Antimicrobial screening of the different extracts (15 μg mm2) was conducted by disc diffusion method. The zones of inhibition demonstrated by the petroleum ether, carbon tetrachloride and dichloromethane fractions ranged from 914 mm, 1113 mm and 920 mm, respectively, compared to kanamycin standard with the zone of inhibition of 2025 mm. In brine shrimp lethality bioassay, the carbon tetrachloride soluble materials demonstrated the highest toxicity with LC50 of 0.83 μg mL1, while petroleum ether and dichloromethane soluble partitionates of the methanolic extract revealed LC50 of 14.94 and 3.29 μg mL1, respectively, in comparison with standard vincristine sulphate with LC50 of 0.812 μg mL1. This is the first report on compounds separation from D. regia, their antimicrobial activity and cytotoxicity

    Polyploidization effect in two diploid cotton (Gossypium herbaceum L. and G. arboreum L.) species by colchicine treatments

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    Anti-mitotic agents such as colchicine have been used to induce polyploidy in various plants. Here we examined the effects of different doses of colchicine on polyploidy induction in two cotton species(Gossypium herbaceum and Gossypium arboreum). The data reveal that the dose of colchicine, treatment duration, genotype and their combined effects on the induction of polyploidy and plant growth rate were statistically significant. Increase of either the concentration of colchicine or treatment duration showed adverse affects on seed viability in both species examined. The colchicine treatmentis more effective when the length of hypocotyls is between 4-7 mm. The buds of G. arboreum treated with 0.9% colchicine exhibited more tetraploid cells sixteen hours post treatment. Among threemethods employed, in vitro treatment of embryos can be conducted in a little space and needs a little amount of colchicines. However, high risk of contamination and high sensitivity of embryos to colchicine is a draw back of this method. Treatment of intact meristems with colchicine requires more amounts of the material and increases the risk of adverse environmental effects. Furthermore, plants treated with this method are susceptible to environmental stimuli including high temperature andshould be kept away from direct sunlight. Together, our data reveal that treatment of the cotton seeds with colchicine was more efficient and reliable compared to other methods examined. The optimumdose of colchicine and the incubation time should be adjusted for each variety under various environmental conditions

    Quantitative infrared thermography resolved leakage current problem in cathodic protection system

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    Leakage current problem can happen in Cathodic Protection (CP) system installation. It could affect the performance of underground facilities such as piping, building structure, and earthing system. Worse can happen is rapid corrosion where disturbance to plant operation plus expensive maintenance cost. Occasionally, if it seems, tracing its root cause could be tedious. The traditional method called line current measurement is still valid effective. It involves isolating one by one of the affected underground structures. The recent methods are Close Interval Potential Survey and Pipeline Current Mapper were better and faster. On top of the mentioned method, there is a need to enhance further by synthesizing with the latest visual methods. Therefore, this paper describes research works on Infrared Thermography Quantitative (IRTQ) method as resolution of leakage current problem in CP system. The scope of study merely focuses on tracing the root cause of leakage current occurring at the CP system lube base oil plant. The results of experiment adherence to the hypothesis drawn. Consequently, res

    Normal Mode Determination of Perovskite Crystal Structures with Octahedral Rotations: Theory and Applications

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    Nuclear site analysis methods are used to enumerate the normal modes of ABX3ABX_{3} perovskite polymorphs with octahedral rotations. We provide the modes of the fourteen subgroups of the cubic aristotype describing the Glazer octahedral tilt patterns, which are obtained from rotations of the BX6BX_{6} octahedra with different sense and amplitude about high symmetry axes. We tabulate all normal modes of each tilt system and specify the contribution of each atomic species to the mode displacement pattern, elucidating the physical meaning of the symmetry unique modes. We have systematically generated 705 schematic atomic displacement patterns for the normal modes of all 15 (14 rotated + 1 unrotated) Glazer tilt systems. We show through some illustrative examples how to use these tables to identify the octahedral rotations, symmetric breathing, and first-order Jahn-Teller anti-symmetric breathing distortions of the BX6BX_{6} octahedra, and the associated Raman selection rules. We anticipate that these tables and schematics will be useful in understanding the lattice dynamics of bulk perovskites and would serve as reference point in elucidating the atomic origin of a wide range of physical properties in synthetic perovskite thin films and superlattices.Comment: 17 pages, 3 figures, 17 tables. Supporting information accessed through link specified within manuscrip
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