Recent achievements in ab initio modelling of liquid water

The application of newly developed first-principle modeling techniques to liquid water deepens our understanding of the microscopic origins of its unusual macroscopic properties and behaviour. Here, we review two novel ab initio computational methods: second-generation Car-Parrinello molecular dynamics and decomposition analysis based on absolutely localized molecular orbitals. We show that these two methods in combination not only enable ab initio molecular dynamics simulations on previously inaccessible time and length scales, but also provide unprecedented insights into the nature of hydrogen bonding between water molecules. We discuss recent applications of these methods to water clusters and bulk water.Comment: 23 pages, 17 figure

Ab initio quality neural-network potential for sodium

An interatomic potential for high-pressure high-temperature (HPHT) crystalline and liquid phases of sodium is created using a neural-network (NN) representation of the ab initio potential energy surface. It is demonstrated that the NN potential provides an ab initio quality description of multiple properties of liquid sodium and bcc, fcc, cI16 crystal phases in the P-T region up to 120 GPa and 1200 K. The unique combination of computational efficiency of the NN potential and its ability to reproduce quantitatively experimental properties of sodium in the wide P-T range enables molecular dynamics simulations of physicochemical processes in HPHT sodium of unprecedented quality.Comment: 8 pages, 11 figures, 2 table

Implementasi Algoritma Enkripsi Citra Digital Menggunakan Skema Tranposisi Berbasis Fungsi Chaos

Algoritma enkripsi citra digital yang dikembangkan dalam paper ini ditujukansebagai alternatif dalam mengamankan informasi citra tersebut. Lenaha yangdilakukan adalah dengan menggunakan skema transposisi yang berbasis fungsichaos, yaitu fungsi Arnold\u27s cat map. Fungsi tersebut berfungsi sebagai bentuktransposisi atau pertukaran posisi dari informasi data aslinya. Akan ditetapkanskema transposisi tertentu untuk mengacak informasi asli sehingga sulit untukdibaca kembali oleh pihak ketiga. Selanjutnya dilakukan pengujian secarapraktis. Pengujian dilakukan untuk beragam data berupa citra digital denganberbagai ukuran. Hasil analisis pengujian secara praktis menunjukkan bahwaruang kunci yang dihasilkan sangat jauh lebih besar dan tingkat sensitivitasnyasangat jauh lebih kecil

Pemeliharaan Ikan Gurami (Osphoronemus Gouramy Lac.) Dalam Wadah Akuarium Diberi Pakan Cacing Sutra (Tubifex SP) Pada Strata Vertikal

This experiment aims to look at the effect of feeding silk worms (Tubifex sp) on the vertical strata in the aquarium container in the maintenance of carp (Osphoronemus gourami). This research was carried out for 30 days with a completely randomized design with 4 treatments and 3 repetitions. Treatment A (top feeding zone), B (middle feeding zone 1), C (middle feeding zone 2), and treatment D (zone bottom-feeding).After analyzed by ANOVA and LSD (Significant Difference) research shows that the average biomass growth body length and weight of the fish is best in treatment C respectively by 6.82 cm and 3.30 grams of the water level 10 cm zone of basic aquarium (P <0.5). While the average percentage of the best survival was also contained in C treatment that is equal to 98%

CryoEM structure of the human SLC4A4 sodium-coupled acid-base transporter NBCe1.

Na+-coupled acid-base transporters play essential roles in human biology. Their dysfunction has been linked to cancer, heart, and brain disease. High-resolution structures of mammalian Na+-coupled acid-base transporters are not available. The sodium-bicarbonate cotransporter NBCe1 functions in multiple organs and its mutations cause blindness, abnormal growth and blood chemistry, migraines, and impaired cognitive function. Here, we have determined the structure of the membrane domain dimer of human NBCe1 at 3.9 Å resolution by cryo electron microscopy. Our atomic model and functional mutagenesis revealed the ion accessibility pathway and the ion coordination site, the latter containing residues involved in human disease-causing mutations. We identified a small number of residues within the ion coordination site whose modification transformed NBCe1 into an anion exchanger. Our data suggest that symporters and exchangers utilize comparable transport machinery and that subtle differences in their substrate-binding regions have very significant effects on their transport mode