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Singaraja, Indonesia

The Ganesha University of Education is a university located in Indonesia. The university has been previously known by the name IKIP Singaraja. Wikipedia.

Mudianta I.W.,University of Queensland | Mudianta I.W.,Ganesha University of Education | Katavic P.L.,University of Queensland | Lambert L.K.,University of Queensland | And 5 more authors.
Tetrahedron | Year: 2010

Chemical analysis of an Indonesian sponge sample has provided three new 3-alkylpiperidine alkaloids, tetradehydrohaliclonacyclamine A, its mono-N-oxide derivative, and a 2-epi isomer. The absolute structure of tetradehydrohaliclonacyclamine A has been established by X-ray crystallography from anomalous dispersion effects using Cu radiation, which determined that the absolute configuration is 2S, 3S, 7S, 9S while an HPLC study revealed that the alkaloid is enantiomerically pure. © 2010 Elsevier Ltd. All rights reserved. Source

Seidel M.,University of Oldenburg | Beck M.,University of Oldenburg | Riedel T.,University of Oldenburg | Waska H.,University of Oldenburg | And 6 more authors.
Geochimica et Cosmochimica Acta | Year: 2014

Seawater circulation in permeable coastal sediments is driven by tidal changes in hydraulic gradients. The resulting submarine groundwater discharge is a source of nutrients and dissolved organic matter (DOM) to the water column. Yet, little is known about the cycling of DOM within tidal sediments, because the molecular DOM characterization remains analytically challenging. One technique that can dissect the multitude of molecules in DOM is ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS). To aim at a high resolution DOM analysis we study the seasonal turnover and marine and terrestrial sources of DOM in an intertidal creek bank of the southern North Sea down to 3m depth and link the biogeochemical processes to FT-ICR-MS data and the analyses of inorganic porewater chemistry, δ13C of solid-phase extracted dissolved organic carbon (SPE-DOC), dissolved black carbon (DBC) and dissolved carbohydrates (DCHO). Increasing concentrations of dissolved Fe, Mn, P, total alkalinity, dissolved nitrogen, DOC and a concomitant decrease of sulfate along the seawater circulation path from the upper tidal flat to the tidal flat margin indicate continuous microbial activity. The relative increase of Si concentrations, unsaturated aliphatics, peptide molecular formulae and isotopically more 13C-enriched SPE-DOC towards the tidal flat margin suggests that remineralization processes mobilize DOM from buried algal (diatoms) and microbial biomass. Porewater in sediments <100cm depth contains 13C-depleted SPE-DOC and highly unsaturated compounds which are probably derived from eroded peats, suggesting rapid removal of bioavailable marine DOM such as DCHO from the water column and selective enrichment of terrestrial DOM. DBC concentrations are highest in the discharging porewater close to the tidal creek suggesting that the intertidal flat is an important DBC source to the coastal ocean. Porewater DOM accumulating at the low water line is enriched in N and S. We hypothesize that this is partly due to DOM reacting with dissolved sulfide and ammonium which may increase the refractory character of the DOM, hence making it less bioavailable for in situ active microbes. © 2014 Elsevier Ltd. Source

Cheney K.L.,University of Queensland | White A.,University of Queensland | Mudianta I.W.,University of Queensland | Mudianta I.W.,Ganesha University of Education | And 5 more authors.
PLoS ONE | Year: 2016

Natural products play an invaluable role as a starting point in the drug discovery process, and plants and animals use many interesting biologically active natural products as a chemical defense mechanism against predators. Among marine organisms, many nudibranch gastropods are known to derive defensive metabolites from the sponges they eat. Here we investigated the putative sequestration of the toxic compound latrunculin A-a 16-membered macrolide that prevents actin polymerization within cellular processes-which has been identified from sponge sources, by five closely related nudibranch molluscs of the genus Chromodoris. Only latrunculin A was present in the rim of the mantle of these species, where storage reservoirs containing secondary metabolites are located, whilst a variety of secondary metabolites were found in their viscera. The species studied thus selectively accumulate latrunculin A in the part of the mantle that is more exposed to potential predators. This study also demonstrates that latrunculin-containing sponges are not their sole food source. Latrunculin A was found to be several times more potent than other compounds present in these species of nudibranchs when tested by in vitro and in vivo toxicity assays. Anti-feedant assays also indicated that latrunculin A was unpalatable to rock pool shrimps, in a dose-dependent manner. These findings led us to propose that this group of nudibranchs has evolved means both to protect themselves from the toxicity of latrunculin A, and to accumulate this compound in the mantle rim for defensive purposes. The precise mechanism by which the nudibranchs sequester such a potent compound from sponges without disrupting their own key physiological processes is unclear, but this work paves the way for future studies in this direction. Finally, the possible occurrence of both visual and chemosensory Möllerian mimicry in the studied species is discussed. © 2016 Cheney et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Source

Purnama I.K.E.,Sepuluh Nopember Institute of Technology | Aryanto K.Y.E.,Ganesha University of Education | Wilkinson M.H.F.,University of Groningen
International Journal of E-Health and Medical Communications | Year: 2010

Retinal blood vessels can give information about abnormalities or disease by examining its pathological changes. One abnormality is diabetic retinopathy, characterized by a disorder of retinal blood vessels resulting from diabetes mellitus. Currently, diabetic retinopathy is one of the major causes of human vision abnormalities and blindness. Hence, early detection can lead to proper treatment, and segmentation of the abnormality provides a map of retinal vessels that can facilitate the assessment of the characteristics of these vessels. In this paper, the authors propose a new method, consisting of a sequence of procedures, to segment blood vessels in a retinal image. In the method, attribute filtering with a so-called Max-Tree is used to represent the image based on its gray value. The filtering process is done using the branches filtering approach in which the tree branches are selected based on the non-compactness of the nodes. The selection is started from the leaves. This experiment was performed on 40 retinal images, and utilized the manual segmentation created by an observer to validate the results. The proposed method can deliver an average accuracy of 94.21%. Copyright © 2010, IGI Global. Source

Dantes K.R.,Ganesha University of Education
International Journal of Applied Engineering Research | Year: 2015

The aims of this reseach is to obtained push metal v belt life time developed using austenitic AISI 205 material for Continously Variable Transmission (CVT). By using analytical methods, the reseach focused on tensile stress of steel ring and shear stress of pulley element contact.Thermal stress and bending stress occured on push metal v belt components. The result showed at ratio > 1 have 3,9106x105 cycle. Fo ratio =1 and ratio <1, the life time were 3,6522 x 105 cycle and 3,1282 x 105 cycle. © Research India Publications. Source

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