7,436 research outputs found

    Diversity of Antibacterial Compounds From Eucheuma Serra, Halimeda Opuntia, and Hydroclathrus Clathratus

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    Fourteen compounds were isolated from acetone extracts of three species of seaweeds (Eucheuma serra, a red seaweed, Halimeda opuntia, a green seaweed, and Hydroclathrus clathratus, a brown seaweed) using bioautographic TLC methods and identified using GC-MS. From Eucheuma serra were isolated 8 compounds (3 fatty acids, 3 steroids, and 2 aldehyds). Only two compounds of fatty acid camefrom Halimeda opuntia, whereas Hydroclathrus clathratus produced 6 compounds (4 fatty acids, one compound each of steroid and ether). All isolated single compoundswere tested for their antibacterial activities by the agar diffusion method against the Gram-positive bacteria Staphylococcus aureus, Bacillus subtilis and Streptococcusfaecalis, and the Gram-negative bacteria Echerichia coli, Pseudomonas aeruginosa and Salmonella typhimurium. All 14 compounds showed activity against Gram-positivebacteria, especially Bacillus subtilis, and only 2 compounds showed activity against Gram-negative bacteria Escherichia coli. Nine compounds showed activity against Staphylococcus aureus, and 4 compounds showed activity against Streptococcusfaecalis. All compounds were not active against Pseudomonas aeruginosa andSalmonella typhimurium bacteria. This study indicated that there is indeed a diversityboth in kinds and in molecular structures of the antibacterial substances

    Ethnobotany Study of Seaweed Diversity and Its Utilization in Warambadi, Panguhalodo Areas of East Sumba District

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    This paper reports the ethnobotany study of seaweed diversity in Warambadi –Panguhalodo areas of East Sumba District, the island of Sumba. The study recorded19 genera of 54 species of seaweed, which were utilized as food or edible seaweed.The group consisted of 17 species of green algae, 17 species of red algae, and 20species of brown algae. The study also reported that 18 genera of 38 species weretraditionally utilized for medicinal purposes as herbal medicine. The herbal speciesconsisted of 7 species of green algae, 13 species of red algae, and 18 species ofbrown algae.Seaweed is traditionally consumed as food in various forms: raw as salad and vegetable,as pickle with sauce of allspice or with vinegar, as relish or sweetened jellies and alsocooked for vegetable soup. As herbal medicine seaweed is usually used for traditionalcosmetics, as antipyretic and antiseptic, as vermifuges, and treatments for cough andasthma, hemorrhoid, nosebleed and boils, goiter and scrofula, stomach ailments andurinary diseases.Indigenous knowledge on seaweed still exist and are continually employed bypeople living in particular areas such as the Sumba and Sabu ethnic groups. Yet,the knowledge is gradually decreasing due to localities, socio-economic change andcultural development

    Non-Hermitian Quantum Mechanics with Minimal Length Uncertainty

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    We study non-Hermitian quantum mechanics in the presence of a minimal length. In particular we obtain exact solutions of a non-Hermitian displaced harmonic oscillator and the Swanson model with minimal length uncertainty. The spectrum in both the cases are found to be real. It is also shown that the models are η\eta pseudo-Hermitian and the metric operator is found explicitly in both the cases

    A computational model for path loss in wireless sensor networks in orchard environments.

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    A computational model for radio wave propagation through tree orchards is presented. Trees are modeled as collections of branches, geometrically approximated by cylinders, whose dimensions are determined on the basis of measurements in a cherry orchard. Tree canopies are modeled as dielectric spheres of appropriate size. A single row of trees was modeled by creating copies of a representative tree model positioned on top of a rectangular, lossy dielectric slab that simulated the ground. The complete scattering model, including soil and trees, enhanced by periodicity conditions corresponding to the array, was characterized via a commercial computational software tool for simulating the wave propagation by means of the Finite Element Method. The attenuation of the simulated signal was compared to measurements taken in the cherry orchard, using two ZigBee receiver-transmitter modules. Near the top of the tree canopies (at 3 m), the predicted attenuation was close to the measured one-just slightly underestimated. However, at 1.5 m the solver underestimated the measured attenuation significantly, especially when leaves were present and, as distances grew longer. This suggests that the effects of scattering from neighboring tree rows need to be incorporated into the model. However, complex geometries result in ill conditioned linear systems that affect the solver's convergence
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