ATP synthesis and pyrophosphate-driven proton transport in tonoplast-enriched vesicles isolated from Catharanthus roseus

AbstractIn the presence of PPi as an energy source, the tonoplast-bound inorganic pyrophosphatase from Catharanthus roseus cells is able to create a proton-gradient which can drive the synthesis of ATP from ADP and Pi. ATP synthesis is linked to the pH-gradient dissipation as monitored by the recovery of the fluorescence intensity of quinacrine and by the amount of synthesized ATP measured by the bioluminescent luciferin/luciferase assay. Proton gradient and ATP synthesis were suppressed by the protonic ionophore gramicidin D

PERANCANGAN IDENTITAS VISUAL DESTINASI WISATA PULAU MERAK KECIL PASCA TSUNAMI SELAT SUNDA 22 DESEMBER 2018

Pada tanggal 22 Desember 2018 yang lalu terjadi Tsunami Selat Sunda mengakibatkan Provinsi Banten atau lebih tepatnya di Kota Cilegon mengalami dampak yang cukup besar terutama di sebagian wilayah Pantai Anyer serta daerah Pelabuhan Merak. Hal ini juga sudah pasti berdampak pada penurunan sektor pariwisata Kota Cilegon. Bencana alam ini juga mengakibatkan destinasi wisata yang berada di dekat dengan laut terkena dampaknya, beberapa fasilitas hancur dan perlu waktu untuk perbaikan fasilitas tersebut. Namun ada beberapa yang tidak terlalu terkena dampak yang besar dari Tsunami Selat Sunda ini, yaitu destinasi wisata Pulau Merak Kecil. Pulau Merak Kecil secara fasilitas masih sangat bagus dan tidak mengalami kerusakan yang parah akan tetapi pulau ini tetap mengalami penurunan jumlah pengunjung. Hal ini dikarekanan masyarakat atau wisatawan masih takut untuk datang atau mengunjungi kawasan ini pasca Tsunami Selat Sunda. Oleh karena itu, perlu dibangun atau dirancang sebuah citra baru destinasi wisata Pulau Merak Kecil pasca Tsunami Selat Sunda agar masyarakat dan calon wisatawan tertarik kembali untuk datang dan mengunjungi kedua pulau ini. Selain itu juga Pulau Merak Kecil ini perlu adanya perancangan identitas visual untuk menarik peminat karena pulau ini belum memiliki identitas visual sama sekali dan juga media promosinya. Dengan adanya permasalahan yang sudah disebutkan di atas menjadi tujuan dari penelitian ini. Penelitian di daerah kota Cilegon dan sekitar Pulau Merak Kecil menggunakan metode data pustaka, observasi, wawancara dan kuesioner serta menggunakan analisis matriks perbandingan. Kata kunci : Destinasi Wisata, Pulau Merak Kecil, Identitas Visual, Pasca Tsunami Selat Sund

Evaluación de la metodología Roger Holmberg para el diseño de túneles mineros

Tesis (Ingeniero Civil en Minas)Esta tesis quiere plantear el desarrollo de la metodología de Roger Holmberg para el diseño de avance de túneles mineros, metodología que se muestra como un paso a paso de varios cálculos predefinidos para el camino al mejor diseño de un diagrama de disparo para la frente de un túnel. A pesar de mostrarse como fácil en su aplicación los túneles tienen distintas dimensiones, formas y están sujetos a las propiedades del macizo rocoso que no posee características constantes conforme se avanza en los desarrollos. Se realizó una búsqueda de casos en lo que se ha implementado y se quiere realizar una guía de la correcta implementación del método cualquiera sea el diseño y condiciones que se presenten en un proyecto siendo un aporte para futuros ingenieros en minas y cualquier profesional que desee generar conocimientos en la creación de una malla de perforación

Site symmetry and crystal symmetry: a spherical tensor analysis

The relation between the properties of a specific crystallographic site and the properties of the full crystal is discussed by using spherical tensors. The concept of spherical tensors is introduced and the way it transforms under the symmetry operations of the site and from site to site is described in detail. The law of spherical tensor coupling is given and illustrated with the example of the electric dipole and quadrupole transitions in x-ray absorption spectroscopy. The main application of the formalism is the reduction of computation time in the calculation of the properties of crystals by band structure methods. The general approach is illustrated by the examples of substitutional chromium in spinel and substitutional vanadium in garnet.Comment: 27 pages, 3 figure

Measurement of Magnetic Moment at the Atomic Scale in a High TC Molecular Based Magnet

The molecular-based magnet Cs^(I) [Ni^(II) Cr^(III) (CN)6]-2H2O is a ferromagnetic with a Curie temperature TC ) 90 K. Its structure consists of face-centered cubic lattice of Ni^(II) ions connected by Cr(CN)6 entities. We have recorded X-ray magnetic circular dichroism (XMCD) at nickel L2,3 edges. It clearly evidences that nickel(II) is in a high-spin configuration and ferromagnetically coupled to the surrounding Cr^(III) . Through ligand field multiplet calculations, we have determined the total magnetic moment carried by Ni^(II) . Special attention has been paid to the magnetic anisotropy that complicates the calculation of the cross section for a powder. By using sum rules derived for XMCD, it has been possible to extract the orbital and spin contributions to the total magnetic moment. A somewhat too small magnetic moment is found on nickel. A complete calculation taking into account the multiplet coupling effect and the covalent hybridization allowed to determine the precise ground state of nickel and showed that hybridization cannot be responsible for the experimental low nickel magnetic moment. The origin of this effect is discussed

X-ray Linear Dichroism in cubic compounds: the case of Cr3+ in MgAl2O4

The angular dependence (x-ray linear dichroism) of the Cr K pre-edge in MgAl2O4:Cr3+ spinel is measured by means of x-ray absorption near edge structure spectroscopy (XANES) and compared to calculations based on density functional theory (DFT) and ligand field multiplet theory (LFM). We also present an efficient method, based on symmetry considerations, to compute the dichroism of the cubic crystal starting from the dichroism of a single substitutional site. DFT shows that the electric dipole transitions do not contribute to the features visible in the pre-edge and provides a clear vision of the assignment of the 1s-->3d transitions. However, DFT is unable to reproduce quantitatively the angular dependence of the pre-edge, which is, on the other side, well reproduced by LFM calculations. The most relevant factors determining the dichroism of Cr K pre-edge are identified as the site distortion and 3d-3d electronic repulsion. From this combined DFT, LFM approach is concluded that when the pre-edge features are more intense than 4 % of the edge jump, pure quadrupole transitions cannot explain alone the origin of the pre-edge. Finally, the shape of the dichroic signal is more sensitive than the isotropic spectrum to the trigonal distortion of the substitutional site. This suggests the possibility to obtain quantitative information on site distortion from the x-ray linear dichroism by performing angular dependent measurements on single crystals

Determination of the cation site distribution of the spinel in multiferroic CoFe2O4 / BaTiO3 layers by X-ray photoelectron spectroscopy

International audienceThe properties of CoFe2O4/BaTiO3 artificial multiferroic multilayers strongly depend on the crystalline structure, the stoichiometry and the cation distribution between octahedral (Oh) and tetrahedral (Td) sites (inversion factor). In the present study, we have investigated epitaxial CoFe2O4 layers grown on BaTiO3, with different Co/Fe ratios. We determined the cation distribution in our samples by X-ray magnetic circular dichroism (XMCD), a well accepted method to do so, and by X-ray photoelectron spectroscopy (XPS), using a fitting method based on physical considerations. We observed that our XPS approach converged on results consistent with XMCD measurements made on the same samples. Thus, within a careful decomposition based on individual chemical environments it is shown that XPS is fully able to determine the actual inversion factor