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Makara Journal of Science
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  This is an Open Access Journal Open Access journal
ISSN (Print) 2339-1995 - ISSN (Online) 2356-0851
Published by Universitas Indonesia Homepage  [20 journals]
  • Optimization of Laccase Adsorption-Desorption Behaviors on Multi-Walled
           Carbon Nanotubes for Enzymatic Biocathodes

    • Authors: Alex Lukmanto Suherman, Abdelkader Zebda, Donald K. Martin
      Abstract: Laccase adsorption-desorption behaviors on the surface of multi-walled carbon nanotubes (MWCNTs) were investigated using spectrophotometry and voltammetry. The optimum condition for laccase adsorption is 5.0 mg/mL of laccase in 0.01 M phosphate-buffered saline (PBS) at pH 5.0. Laccase adsorption is a reversible phenomenon that is dependent upon the nature of MWCNTs and the concentration of ionic strength in the laccase solution. Chitosan was functionalized as a nanoporous reservoir to minimize laccase desorption. Chitosan was found to protect approximately 97.2% of the adsorbed laccase from MWCNTs during the first six hours of observation. The three-dimensional (3D) biocathode, MWCNTs-laccase-chitosan with a 0.2 cm2 geometric area, was shown to have a stable open circuit potential (OCP) of 0.55 V, a current density of 0.33 mA cm-2 at 0.2 V vs. saturated calomel electrode (SCE), and a stable current for 20 hours of successive measurements. This report provides a new insight into the study of a high-performance laccase-based biocathode via optimization of adsorption and minimization of desorption phenomena.
      PubDate: 2018-04-03
      Issue No: Vol. 22 (2018)
       
  • Determination of Polycyclic Aromatic Hydrocarbons (PAHs) Using
           Environmentally Friendly Liquid Chromatography

    • Authors: Asep Kurnia, Lee Wah Lim, Toyohide Takeuchi
      Abstract:  An analytical method to determine polycyclic aromatic hydrocarbons (PAHs) is required to obtain high-quality analytical results. The purpose of this study is to achieve good separation of a few PAHs by using environmentally friendly liquid chromatography. Accordingly, a liquid chromatograph incorporating a fluorescence detector, UV detector, and a capillary column is employed herein to simultaneously minimize the use of chemicals and obtain analytical results better than those obtained using a conventional column. Observation parameter include single analysis of each PAH, method validation, the new stationary phase, the effect of mobile phase concentration, and Quencher effect. The PAHs tested include naphthalene, phenanthrene, anthracene, fluoranthene, and pyrene. The test results show that when using an acetonitrile concentration of 100%, the retention times of different PAHs do not differ significantly. Furthermore, upon decreasing the acetonitrile concentration, the retention time increases, and better separation was achieved. The value ranges of precision, LOD, LOQ, and linearity are 3.43–12.42%, 4.7–15.1 mg/L, 15.6–50.5 mg/L, and 0.87–0.99, respectively. The new Sil-S-ImC30 stationary phase showed good results in terms of separation of PAHs. Likewise, the use of 60, 70, 80, and 90% acetonitrile as the mobile phase in combination with 0.03 M acrylamide as the quencher affected retention time but not separation. 
      PubDate: 2018-04-02
      Issue No: Vol. 22 (2018)
       
  • Single Nucleotide Polymorphism within the Promoter Region of Cynomolgus
           Monkey LDLR Gene

    • Authors: Achmad - Taher, Dedy Duryadi Solihin, Sulistiyani Sulistiyani, Dewi Apri Astuti, Dondin Sajuthi
      Abstract: The cynomolgus monkey (Macaca fascicularis) is one of the most common nonhuman primates used as an animal model in biomedical research related to atherosclerosis. However, little is known about genetic variation in the low density lipoprotein receptor (LDLR) gene, its effect on cholesterol levels, and associated risks of atherosclerosis. Therefore this study aimed to identify genetic polymorphisms, namely single nucleotide polymorphisms (SNPs), within the promoter region of LDLR and their relationship with animal responsiveness to hypercholesterolemia due to an atherogenic diet. In this research, SNPs were studied using DNA isolated from 22 cynomolgus monkeys obtained from a previous study, consisting of two hyporesponders, 19 hyperresponders, and one extreme case. The result showed that two SNPs existed in the promoter region, namely g.−169T>C and g.−265G>A. SNP g.−265G>A showed linkages with extreme responsiveness and can be used as a potential genetic marker for extreme animals. The result of this study has extended our knowledge of polymorphism in the LDLR gene and its use in the selection of cynomolgus monkeys as animal models in research on hypercholesterolemia and atherosclerosis.
      PubDate: 2018-03-26
      Issue No: Vol. 22 (2018)
       
  • Craniofacial Shape of Arfak People Based on Geometric Morphometric
           Features

    • Authors: Elda Irma Jeanne Joice, Bambang Suryobroto, Sri Budiarti, Alex Hartana
      Abstract:  Face and cranial (craniofacial) shape is highly specific to the individual; therefore, craniofacial shape is often used to identify individuals and to analyze variability in the human population. Previous studies, consisting only of verbal descriptions, suggested that the cranial shape of the Papuan people was highly variable. Despite their usefulness, verbal descriptions cannot fully demonstrate common and local variation in cranial shape. They also cannot be used to extract the general trend of variation or to group face shapes based on their similarity. Here we attempt to apply geometric analysis, a method of shape analysis, to measure facial anatomical structural landmarks of Papuan people. The craniofacial shape of Papuan people was constructed from those of Arfak people based on 16 anatomic landmarks on the lateral side. Arfak is one of the traditional Papuan tribes in Manokwari, West Papua Province. Our result showed great variation in craniofacial shapes among the Arfak. The nose, chin, and mandible differed significantly, whereas other parts of the face were relatively stable and showed small variations. These differences reflected variations in the facial growth rate. The high level of diversity thus indicates that some parts of the face have higher plasticity in their growth pattern than others. 
      PubDate: 2018-03-26
      Issue No: Vol. 22 (2018)
       
  • Characterizing Particle Board Made of Oil Palm Empty Fruit Bunch Using
           Central Composite Design

    • Authors: Mirna Rahmah Lubis, Teuku Maimun, Jon Kardi, Rifdullah Bikri Masra
      Abstract: Particle board was made using processed oil palm empty fruit bunch and casein glue. This research used two factor variables and eight response variables to determine the best matrix/filler ratio and compression pressure for particle board production. The factor variables, (matrix/filler ratio and compression pressure), determined the response variables: modulus of rupture, water content, density, tensile strength, and both endothermic-and-exothermic temperatures and heats. This research aimed to optimize the mechanical and physical property of particle boards by using the bunch/glue ratio. The processing of data was undertaken by Response Surface Method (RSM) with Central Composite Design (CCD). The optimal conditions under which particle board created were at matrix/filler ratio of 50:50 and compression pressure of 3.53 kg/cm2; resulting in a modulus of rupture of 325.32 kg/cm2, water content of 0.009%, density 0.826 g/cm3, and tensile strength of 2.573 kg/cm2. This research also indicates that casein glue results in particle board with optimum parameters of endothermic temperature of 247.74 °C,
      PubDate: 2018-03-26
      Issue No: Vol. 22 (2018)
       
  • Assisted Surface-state Recombination of Orange-peel Carbon Nanodots in
           Various Matrices

    • Authors: Siti Fatimah, Isnaeni Isnaeni, Dahlang Tahir
      Abstract: The contentious origin of the luminescence of carbon nanodots (CDs) has attracted considerable attention. In this work, we synthesized CDs from orange peel by using a microwave-assisted technique. We investigated the optical properties of the synthesized CDs. Moreover, we studied the effect of matrix addition on the optical properties of CDs. We found that matrix addition significantly influences the absorbance and photoluminescence of CDs. Shifts in absorbance peak intensity and emission peak wavelength indicated that the bonding of matrix molecules on the surfaces of the CDs has changed the structures of CDs. This finding is supported by the extended half-life of CDs after matrix addition. Our results will expand research on the use of CDs as phosphorescent materials.
      PubDate: 2018-03-26
      Issue No: Vol. 22 (2018)
       
  • QSAR Studies of Nitrobenzothiazole Derivatives as Antimalarial Agents

    • Authors: Ruslin Hadanu, La Adelin, I Wayan Sutapa
      Abstract: Quantitative Structure and Activity Relationship (QSAR) analyses were carried out for a series of 13 nitrobenzothiazole derivatives as antimalarial compounds to find out the structural relationship of their antimalarial activities against the W2 Plasmodium falciparum strain. The electronic descriptors have been determined using the atomic net charges (q), dipole moment (μ), ELUMO, EHOMO, polarizability (α) and Log P. In addition, the descriptors were calculated through HyperChem for Windows 8.0 using the PM3 semi-empirical method. The antimalarial activities (IC50) were taken from literature [1]. Furthermore, the QSAR model was determined by multiple linear regression (MLR) approach, giving equation model of QSAR: Log IC50 = 41.483 + 54.812 (qC2) – 50.058 (qS3) + 416.766 (qC4) + 440.734 (qC5) – 754.213 (qC7) – 73.721 (qC8) + 246.715 (qC9) + 0.551 (μ) – 13.269 (EHOMO) – 3.404 (ELUMO) + 0.042 (α) + 0.107 (Log P). The most statistically significant QSAR model with correlation coefficients n = 13, (r) = 1.00, (r2) = 1.00, SE = 0, and PRESS = 3.40 were developed by MLR. Based on the model of the above QSAR equation 43 new nitrobenzothiazole derivatives were modeled and 24 of these compounds showed high antimalarial activity. It is recommended that these are synthesized for further investigation 4 new compounds (45, 49, 52 and 55) show equivalent activity to that achieved with chloroquine antimalarial drugs.
      PubDate: 2018-03-26
      Issue No: Vol. 22 (2018)
       
 
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