Judul: Effect of Eucheuma cottonii extract on alcohol-induced spatial memory of DDY mice (Mus musculus) strain
Abstrak: Memori spasial digunakan untuk mengenal ruang, bentuk, arah, jarak, luas dan posisi. Konsumsi alkohol dapat menurunkan fungsi memori dengan meningkatkan pembentukan Reactive Oxygen Species (ROS). Eucheuma cottonii mengandung senyawa antioksidan yang dapat melawan serangan radikal bebas. Penelitian ini bertujuan mengetahui pengaruh pemberian ekstrak alga E. cottonii terhadap memori spasial dan neurogenesis pada hipokampus mencit yang diinduksi alkohol. Mencit dibagi menjadi 5 kelompok. Perlakuan pertama selama tujuh hari mencit kelompok K diberi air, sedangkan kelompok lainnya diberi etanol 50%. Perlakuan kedua selama 14 hari mencit kelompok K dan K- diberi air, kelompok K+ diberi ekstrak Centella asiatica 300 mg/kg BB, kelompok P1 dan P2 diberi ekstrak E. cottonii dengan dosis 250 dan 150 mg/kgBB. Y-maze Alternation Test dan Novel Object Recognition Test digunakan untuk menguji memori spasial. Pengamatan histologi otak dilakukan dengan menghitung densitas sel pada hipokampus berdasarkan morfologinya. Analisis fitokimia menggunakan GC-MS menunjukkan bahwa senyawa aktif yang terkandung dalam ekstrak E. cottonii didominasi oleh senyawa ester, organosilikon, alkana, asam lemak, fenol, alkohol, lakton, terpenoid, keton, alkena, oxaspiro dan organofosforus. Hasil penelitian menunjukkan setelah pemberian ekstrak E. cottonii terjadi peningkatan pada persentase kinerja memori spasial dan neural progenitor cell serta penurunan persentase sel apoptosis yang tidak signifikan., Spatial memory used to recognize space,shape, direction, distance, area and position. Alcohol consumption can reduce memory function by increasing Reactive Oxygen Species (ROS). Eucheuma cottonii contains antioxidant compounds that can fight free radical attacks. This study aims to determine the effect of E. cottonii algae extract on spatial memory and neurogenesis in the hippocampus of alcohol induced mice. Mice were divided into 5 groups. The first treatment in seven days, group K receiving water, the other subjected ethanol 50%. The second treatment in 14 days, involved water for K and K-, Centella asiatica extract 300 mg/kg BW for K+, E. cottonii extract 250 and 150 mg/kg BW for P1 and P2. Y-maze Alternation Test and Novel Object Recognition Test used to test spatial memory. Brain histology observations were carried out by calculating cell density in the hippocampus based on its morphology. The results of GC-MS analysis show that the active compounds contained in the E. cottonii extract are dominated by esters, organosilicons, alkanes, fatty acids, phenols, alcohols, lactones, terpenoids, ketones, alkenes, oxaspiro and organophosphorus. Results indicate an enhancement in spatial memory performance and neural progenitor cell percentage after E. cottonii extract administration, accompanied by a non-significant reduction in apoptotic cells.
Keyword: Alga, Antioksidan, Hipokampus, Novel Object Recognition Test, Y  Maze Alteration Test

Judul: Effects of Alcohol Consumption on Spatial Memory Performance and Neuron Complexity
Abstrak: Alcoholic beverages have always been a common drink all around the globe. The ethanol that is contained inside these alcoholic beverages have been known to have various negative side effects to the brain if consumed excessively. Other articles have claimed a certain moderate amount of alcohol consumption could have beneficial effects on the brain, but no exact concentration limit of consumption has been elaborated to cause damage in the hippocampal area. The objective of this research is examining the effects of alcohol towards neuron complexity and spatial memory performance. Four groups of mice were used as test subjects and were given the solution pre-orally. The first group is the control group which is given water, the second group was given 5% alcohol, the third group was given 15% alcohol, and the fourth group was given commercially sold alcoholic beverage. The mice were given said solutions in the span of 30 days. Spatial memory performance is observed by how a mice scores inside a Y-maze in the span of 5 minutes after 30 days of treatment. Neuron complexity is determined by the number of intersections of dendrites and the maximum angle of neurons inside the Dentate Gyrus (DG) and Cornu Ammonis (CA) region of the hippocampus which is observed by Golgi-Cox staining, photographed with optilab and then analyzed using the ImageJ application. alcohol consumption does not have any significant effect on spatial memory performance nor neuron complexity in the hippocampal area. These findings are not significantly different than the control group, possibly because the treatment is not chronic enough to trigger a significant physiological change.
Keyword: Ethanol, spatial memory, complexity, hippocampus

Judul: Hamiltonian formulation for linear waves motion in two layers fluid
Abstrak: The surface wave could be considered as a wave that separates two fluids, namely water and air. Based on this assumption, it is introduced the interfacial wave, a wave between two layers of fluid with different density. The formulation of interfacial waves motion begins with deriving the base equation of irrotational ideal fluid. Furthermore, according to irrotational fluid assumption, the base equation can be stated in velocity potential. In this derivation, the fluids domain is assumed to be restricted by rigid lid boundary conditions, both at the upper and lower limit. Therefore, the interfacial waves motion can be explained in a hamiltonian formulation. In the hamiltonian formulation, total energy is defined as the sum of kinetic and potential energy. The hamiltonian system is obtained from reduction of kinetic energy by using the Dirichlet Neumann Operator. The resulted kinetic energy equation is nonlinear. Therefore, this form is linearized by first part of the Taylor expansion. This linearization gives a dispersion relation of linear wave. Based on this dispersion relation, the phase speed of the linear wave depends on the density ratio of the two layers fluid.
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