Gadjah Mada University

About: Gadjah Mada University is a education organization based out in Yogyakarta, Indonesia. It is known for research contribution in the topics: Population & Adsorption. The organization has 17307 authors who have published 21389 publications receiving 116561 citations. The organization is also known as: University of Gajah Mada & Universitas Gadjah Mada.

Agrobacterium-mediated transformation of Javanica rice cv. Rojolele

Abstract: The Agrobacterium-mediated transformation system was extended to a famous Javanica rice variety, Rojolele, that is cultivated in Indonesia now. Efficient callus induction from immature and mature seeds of Rojolele did not succeed by any previous method for any rice cultivar. In this study, the callus from mature seeds of Rojolele exhibited a compact and nodular appearance on C medium after the carbon source and medium pH was modified. Scutellum-derived calli from mature seeds were co-cultivated with Agrobacterium tumefaciens strains EHA101 or LBA4404 that carried plasmid pAFT14, which contained the genes for beta-glucuronidase (gus) and hygromycin resistance (hpt). Finally, the transformation efficiency of Rojolele variety using A. tumefaciens strain EHA101 (pAFT14) was improved to about 23%, similar to that of the Japonica rice variety Nipponbare. The seed fertility of transgenic Rojolele was more than 90%. The copy number of the transgene varied from one to three copies in the T(0) transgenic lines. Both the gus and the hpt genes were inherited and expressed in the progeny.

Defect-induced large spin-orbit splitting in monolayer PtSe 2

Abstract: The effect of spin-orbit coupling on the electronic properties of monolayer (ML) ${\mathrm{PtSe}}_{2}$ is dictated by the presence of the crystal inversion symmetry to exhibit a spin-polarized band without the characteristic of spin splitting. Through fully relativistic density-functional theory calculations, we show that large spin-orbit splitting can be induced by introducing point defects. We calculate the stability of native point defects such as a Se vacancy (${\mathrm{V}}_{\text{Se}}$), a Se interstitial (${\mathrm{Se}}_{i}$), a Pt vacancy (${\mathrm{V}}_{\text{Pt}}$), and a Pt interstitial (${\mathrm{Pt}}_{i}$) and find that both the ${\mathrm{V}}_{\text{Se}}$ and ${\mathrm{Se}}_{i}$ have the lowest formation energy. We also find that, in contrast to the ${\mathrm{Se}}_{i}$ case exhibiting spin degeneracy in the defect states, the large spin-orbit splitting up to 152 meV is observed in the defect states of the ${\mathrm{V}}_{\text{Se}}$. Our analyses of orbital contributions to the defect states show that the large spin splitting is originated from the strong hybridization between Pt-${d}_{x{}^{2}+y{}^{2}}+{d}_{xy}$ and Se-${p}_{x}+{p}_{y}$ orbitals. Our study clarifies that the defects play an important role in the spin-splitting properties of the ${\mathrm{PtSe}}_{2}$ ML, which is important for designing future spintronic devices.

GIS mapping of tsunami vulnerability: Case study of the Jembrana regency in Bali, Indonesia

Abstract: The coastal zone is a precious area that sustains many people and various ecosystems of high biological and economic importance. However, ecosystems and human settlements in coastal regions can be vulnerable to natural disasters such as tsunamis. Around Indonesia, seismic activity under the Indian Ocean has caused frequent earthquakes and tsunamis. In this paper, we describe a GIS-based multi-criteria analysis of tsunami vulnerability for the Jembrana Regency in Bali, Indonesia. We used multiple geospatial variables of topographic elevation and slope, topographic relation to tsunami direction, coastal proximity, and coastal shape. We also incorporated expert knowledge by the Analytic Hierarchy Process (AHP) to construct a weighting scheme for the geospatial variables. In order to examine tsunami vulnerability in relation to land use, we overlaid an official land-use map on the tsunami vulnerability map. Buildings as well as residential and agricultural areas were found to be particularly at risk in our study area. GIS-based analyses can aid in a wide range of disaster assessment and facilitate regional planning for management and mitigation of natural disasters such as tsunamis. We expect that the tsunami vulnerability map presented here will contribute to preliminary tsunami mitigation and management efforts in the Jembrana Regency.

Studies on callus induction, plant regeneration and transformation of Javanica rice cultivars

Abstract: The purpose of this study was to develop a reproducible efficient procedure for the transformation of Javanica rice cultivars from Indonesia. Five rice cultivars cultivated in Indonesia now were examined for their capacity on the callus growth, plant regeneration and transformation. Their potential was affected by genotype and medium. Regarding the quality of callus, type I calli produced higher plant regeneration frequency than type II calli. So type I calli were inoculated with A. tumefaciens harboring binary plasmid pAFT14, which had a hygromycin resistance (hpt) gene and a gus gene. In this study, we examined two media for two steps in the tissue culture process for transformation, i.e. callus inducing and plant regeneration. The results show that C-modified medium was the suitable media for callus induction in the most Javanica rice cultivars. Agrobacterium-mediated transformation system has been extended to five Javanica rice cultivars. Among them, Rojolele consistently gave the best performance.