Tony Sumaryada

Bond Model of Second- and Third-Harmonic Generation in Body- and Face-Centered Crystal Structures

In this work, we describe the third- and fourth-rank tensors of body- and face-centered cubic systems and derive the s- and p-polarized SHG far field using the simplified bond-hyperpolarizability model. We also briefly discuss bulk nonlinear sources in such structures: quadrupole contribution, spatial dispersion, electric-field second-harmonic generation, and third-harmonic generation, deriving the corresponding fourth rank tensor. We show that all the third- and fourth-rank tensorial elements require only one independent fitting parameter.

Molecular Interaction Analysis of COX-2 against Curcuminoid and Xanthorizol Ligand as Anti Breast Cancer using Molecular Docking

Breast cancer is one of the most common cancer in the world that occurs in women. Thedevelopment process of cancer is regulated by a variety of pathways that involve various enzymes. COX-2 is an enzyme involved in the inflammatory process in further stages that will play importantroles in breast cancer cells progression. The uses of natural compound from plants give new hope forbreast cancer treatment with minimal side effects. Temulawak is a potential breast cancer drugs because it contains curcuminoid and xanthorizol. Curcumin and xanthorizol has been reported to have chemopreventive effect on colon cancer development. The drug that has same functions of these compounds needed to be examined with various approaches. One of the approach used in this research is molecular docking. Based on ligand analysis with Lipinski and toxicity test using ADMET, curcuminoid and xanthorizol met criteria as medicinal compounds. Curcumin had the highest binding affinity(?G) with the value -9.3 kcal/mol but still under commercial drug celecoxib binding affinity (?G) = -12,5. There were three hydrogen bonds in amino acid Arg 106 and Tyr 341 His 75 which were amino acids in the active side of COX-2. There were 15 amino acids that have similar ties with commercial drug celecoxib. Based on the binding affinity and binding similiarity, curcuminoid and xanthorizol were predicted as compounds that have potential as competitive inhibitor of COX-2 enzyme.

Molecular docking simulation of mangostin derivatives and curcuminoid on maltase- glucoamylase target for searching anti-diabetes drug candidates

The increasing number of diabetes case in Indonesia recently is quite alarming and need to be responded properly by exploring the potential of some Indonesian herbal plants as anti-diabetes drug candidates. In this research molecular docking simulations of some Indonesian herbal compounds (mangostin derivatives and curcuminoid) on Maltase-glucoamylase target has been performed. The patented drug, Miglitol, was used as a control in this research. The results show that all mangostin compounds has a better binding affinity as compared to miglitol’s (-5.30 kcal/mol), with gammamangostin has the strongest binding affinity of -7.60 kcal/mol. The binding site analysis shows that mangostin compounds mostly docked on the similar sites as compared to Miglitol’s, which suggest a similar healing mechanism between those compounds. As the case for curcuminoid, eventhough they have binding affinities stronger than miglitol’s, but they docked mostly on the different sites than miglitol’s, suggesting that unlike mangostin compounds, curcumin does not show a valuable potential as anti-diabetic agent through MGA inhibition.

Elucidation of GB1 Protein Unfolding Mechanism via a Long-timescale Molecular Dynamics Simulation

This study investigates the unfolding mechanism of 1GB1 protein at various simulation temperatures using a long-timescale molecular dynamics simulation. Analysis of structural parameters of molecular dynamics simulation have indicated that the unfolding process of GB1 protein has started at 95 ns for 475 K simulation, and at 745 ps for 500 K simulation. The unfolding process in this simulation exhibit the feature of hydrophobic core collapse model, in which the beta-hairpin destruction precedes the a-helix to coil transition. The unfolding was started with the increasing flexibility of the beta-sheets and hydrophobic core region, continued with beta-hairpins destruction, and ended with a-helix to coil and turn transition. The final structures of GB1 protein after unfolding, suggest an unfinished denaturation of protein as seen from the small remains of α-helix structure.

Local Density of Optical States of an Asymmetric Waveguide Grating at Photonic Band Gap Resonant Wavelength

We have investigated the characteristics of local density of optical states (LDOS) at photonic band gap resonant wavelength of an asymmetric waveguide grating based on Green’s function formulation. It is found that the LDOS of the considered structure exhibits different characteristics in its localization between the upper and lower resonant wavelengths of the corresponding photonic band gap edges.

The effect of spectrum range limitation to the efficiency of Al0.3Ga0.7As/GaAs/InP/Ge multijunction solar cells: a simulation case

The effect of Spectrum Range Limitation (SRL) to the efficiency and performances of multijunction solar cells Al0.3Ga0.7As/GaAs/InP/Ge was investigated using simulation approach. Simulations were done using two different models, first with No Spectrum Range Limitation (NSRL) and the second with SRL. In the first model each subcell (material) was free to absorb AM1.5G solar radiation spectrum from 280 nm up to 2500 nm, while for the second model, the absorption spectrum for each subcell depends on the cut-off wavelength of its previous subcell. For each model, a non-identical current flow in each layer was simulated. The results have shown that SRL dropped the efficiency by almost a half (44.90 %) compared to simulation with NSRL. All current-producing simulations were performed using freely available PC1D program.

Ideal simulation of Al0.3Ga0.7As/InP/Ge multijunction solar cells

Increasing the efficiency of solar cell is one of the most challenging tasks for material scientists nowadays. Computer simulation on the other hand, could be used to maximize this effort. In this paper we present our investigations on Al0.3Ga0.7As/InP/Ge multijunction solar cells. These multijunction solar cells were designed and simulated using PC1D program in two different models. Model 1 focuses on maximizing the efficiency of each subcell, while in model 2 we forced identical current flowing in each subcell. Simulations for both models were performed under ideal conditions of blackbody spectrum at T=6000 K (at the top of atmosphere) and solar intensity of 0.1367 W/cm2. Our results show that model 1 produces efficiency up to 38.86% compared to 20.26% that produced by model 2.