Judul: Penerapan Metode Runge-Kutta Orde Empat Pada Model Infeksi Hiv Sel +
Abstrak: HIV (Human Immunodeficiency Virus) adalah virus yang menyerang sistem kekebalan tubuh manusia dan kemudian menimbulkan AIDS (Acquied Immune Deficiency Syndrome). HIV menyerang sel-sel tertentu dalam sistem kekebalan tubuh yang disebut sel T atau sel + . Sel + adalah sel yang memunyai peran sentral sebagai sistem kekebalan tubuh dan dijadikan sebagai indikator utama untuk mengukur penyebaran infeksi HIV. Dalam tulisan ini disajikan model infeksi HIV pada sel + untuk mengetahui tingkat penyebaran infeksi HIV. Setelah itu dilakukan analisis kestabilan dan penyelesaian numerik menggunakan metode Runge-Kutta orde empat. Penyelesaian numerik ini memperlihatkan penurunan jumlah sel + terhadap waktu. Oleh karena itu dapat diketahui periode laju penurunan cepat dan laju penurunan lambat. Dengan melihat hal itu dapat diketahui langkah pengobatan yang paling tepat terhadap penderita HIV/AIDS.
Keyword: sel CD4+T, model infeksi HIV pada selCD4+T, metode Runge- Kutta orde empat

Judul: Penyelesaian model infeksi HIV pada sel darah Putih (T CD4+) dengan menggunakan metode perturbasi homotopi
Abstrak: Acquired immunodefficiency syndrome (AIDS) is defined as symptoms of human immune system deterioration caused by human immunodefficiency virus (HIV). The virus damages the leucocytes; therefore, once a person is infected by the HIV, his/her immune system will be paralyzed and eventually he/she will not be able to survive from any disease. HIV is transmitted in many ways, such as having unsafe sex, using unsterilized syringe and blood transfusion. Homotopy perturbation method is implemented to give approximate and analytical solutions of nonlinear ordinary differential equation systems as a model for HIV infection of CD4+ T cells. A modification of the homotopy perturbation method (HPM), based on the use of numerical solution, is proposed. Some plots are presented to show the reliability and simplycity of the homotopy perturbation method. The results obtained in this study indicate that the homotopy perturbation method is highly efficient to solve models of HIV infection of cells (T CD4+). Errors resulting from this method is so small that the solution obtained by is very close to the exact solution.
Keyword: 

Judul: Development of Antioxidant Film from Basil Seed (Ocimum citriodourum) Mucilage Incorporated with Thyme Essential Oil.
Abstrak: The objectives of this research was to evaluate the effects of thyme essential oil addition on physical properties and antioxidant activity of lemon basil seed mucilage film. Lemon basil is a common name for the culinary herb (Ocimum citriodourum). This research project investigated the properties of an edible film based on lemon basil seed mucilage (LBSM) incorporated with thyme essential oil (TEO). LBSM (0.4% w/v) films were prepared by adding glycerol as plasticizers at the concentration of 30% w/w based on the weight of LBSM and then incorporated with TEO for antioxidant properties. LBSM films were given different concentrations of TEO (0%, 1%, 2% and 3% v/v) (0% as the control). The result showed that films with 3 % TEO had the highest water vapor permeability (WVP) (3.27±0.38 x10-4g mm/m2d kPa), while the control film showed the lowest WVP (1.36±0.28 x10-4g mm/m2d kPa). Water solubility were decreased with the increase in TEO concentration (p<0.05). 1% TEO films showed the highest tensile strength (5.17±0.54MPa) but lower % elongation at break (11.28±1.86%) compared to the other two films (p<0.05) (excluding the control). Scanning electron microscopy showed that the microstructure of the TEO LBSM films had a critical effect on its physical properties, further supporting the tensile strength and WVP results. The 3% TEO film exhibited the highest radical scavenging activity on DPPH (3.3±0.04 % inhibition) (p<0.05) while the others were very low and had slight difference. Increasing the amount of TEO will increase the antioxidant activity, but further increasing the concentration of TEO will also weaken the physical properties of the film.
Keyword: Lemon basil seed mucilage, edible film, antioxidant, thyme essential oil, film properties