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Makara Journal of Science
Published by Universitas Indonesia
ISSN : 23391995     EISSN : 23560851     DOI : https://doi.org/10.7454/mss
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Makara Journal of Science publishes original research or theoretical papers, notes, and minireviews on new knowledge and research or research applications on current issues in basic sciences, namely: Material Sciences (including: physics, biology, and chemistry); Biochemistry, Genetics, and Molecular Biology (including: microbiology, physiology, ecology, taxonomy and evolution); and Biotechnology.
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Articles 880 Documents
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Role of Indigenous Nitrogen-fixing Bacteria in Promoting Plant Growth on Post Tin Mining Soil Widawati, Sri; Suliasih,
Makara Journal of Science Vol. 23, No. 1
Publisher : UI Scholars Hub

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Abstract

Post tin mining soil is generally marginal with low pH, has poor nutrient content, and is thus unfavorable for plant growth, particularly for Sorghum bicolor, which is a nutrient-demanding plant. Indigenous bacteria are usually used in bioaugmentation to ameliorate environmental degradation due to their ability to adapt well. This research aimed to isolate indigenous nitrogen-fixing bacteria and evaluate its potential for promoting the growth of S. bicolor on post tin mining soil. Nitrogen-fixing bacteria were isolated from post tin mining soil by using specific media and identified by Bergey’s manual. Twenty five isolates were obtained, and eight of them (Azospirillum sp., Azospirillum lipoferum, Azotobacter chroococcum, A. paspalii, and Rhizobium sp.) were identified as nitrogen-fixing bacteria. A greenhouse experiment was conducted using factorial completely randomized design with three replications. The first factors were fertilizers, i.e., NPK; A. lipoferum CBT4 + NPK; A. lipoferum CBT4; and without fertilizer (control). The second factors were soil types, i.e., A (fertile soil from Cibinong), B (soil from Bangka Botanical Garden), C (soil from post tin mines two years after mining), and D (soil from active tin mining). Result showed that Azospirillum lipoferum CBT4 isolated from C (soil from post tin mines two years after mining) exhibited the highest IAA, Ca-P solubilizing ability, and PME-ase activity. This species survived up to a population of 107 CFU/gram soil in the three types of post tin mining soils and could be a potential plant-growth promoting rhizobacteria (PGPR) species for effectively improving the growth of S. bicolor plant on post tin-mining soil.
Determining Soft Layer Thickness Using Ambient Seismic Noise Record Analysis in Kota Baru, South Lampung Ipmawan, Vico Luthfi; Permanasari, Ikah N. P.; Siregar, Rahmat Nawi
Makara Journal of Science Vol. 23, No. 1
Publisher : UI Scholars Hub

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Abstract

The local site effect of an earthquake can be calculated through an analysis of short period ambient noise, known as microtremors. The fundamental frequency and amplification factors can be identified by analyzing microtremors using the Horizontal to Vertical Spectral Ratio (HVSR) method. This information can then be used to determine the thickness of the soft layers of sediment. This study analyzed microtremor recordings made in Kota Baru, South Lampung. The amplification factor range according to the HVSR method was 2.3 to 6.17, and the fundamental frequency range was 0.56 Hz to 1.46 Hz. Some spectrums exhibit two peaks with f0 > f1. We suggest that these locations have two layers with significant impedance contrast, which aligns with the geological conditions. The center of the Kota Baru area, especially the region around T11 and T15, has a thicker soft layer than the outskirts; in the central area, the soft layer is approximately 85 to 102 meters thick. The western part of the analyzed area has a shallower soft layer of about 32 to 46 meters. The analysis indicates that the western part has less amplification because it is shallower than the other parts of the analyzed region.
Decontamination of Ni(II) and Co(II) ions from Aqueous Medium using the Cola Lepidota Pericarp Oladimeji, Adesanmi Segun; Uzoamaka, Ibezim Ezeani Millicent; Chidi, Obi
Makara Journal of Science Vol. 23, No. 1
Publisher : UI Scholars Hub

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Abstract

In this study, the batch adsorption of Ni(II) and Co(II) ions was investigated by using the pericarp of Cola lepidota as the adsorbent. The pulverized sample was modified using sodium hydroxide. In addition, the effects of pH, particle size, contact time, temperature, and initial concentration on adsorption were investigated. Results revealed that maximum adsorption of metal ions are observed at pH of 6, a contact time of 60 min, and a temperature of 70 ºC. In addition, modification was to considerably impact the effectiveness of the adsorbent. The percentage removal of the metal ions on the modified (MCLR) and unmodified adsorbents (UCLR) followed increasing order of Co(II) ion on UCLR < Ni(II) ion on UCLR < Co(II) ion on the NaOH-modified adsorbent < Ni(II) ion on the NaOH-modified adsorbent. Equilibrium data were analyzed by the Langmuir and Freundlich isotherm models, and kinetic studies were carried out using pseudo-first-order and pseudo-second-order models. The adsorption data were well fitted to the Freundlich isotherm model equation, with correlation coefficient (R2) values greater than 0.950, and the pseudo-second-order kinetic model, with correlation coefficient (R2) values greater than 0.990. The monolayer adsorption capacities for modified C. lepidota residue and unmodified C. lepidota residue were 5.890 mg/g and 5.627 mg/g, respectively.
Volatile Compounds Detected in Coconut Shell Liquid Smoke through Pyrolysis at a Fractioning Temperature of 350-420 C Hadanu, Ruslin; Apituley, Daniel Ambrosius Nicholas
Makara Journal of Science Vol. 20, No. 3
Publisher : UI Scholars Hub

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Abstract

This study evaluated the volatile components of liquid smoke from coconut shells obtained through the pyrolysis process at fraction 350-420 °C. The volatile compounds of liquid smoke from a coconut shell were analyzed using gas chromatography and mass spectrometry (GC-MS). Nineteen peaks were detected by GC-MS in the coconut shell liquid smoke, and 19 compounds also were identified. The volatile compounds were identified as follows based on their function group’s composition percentage: phenol (90.75%), carbonyl (3.71%), alcohol (1.81%), and benzene (3.73%), respectively. The liquid smoke contains a high ratio of phenol derivatives (90.75%) in volatile profile. The phenol derivatives were the major volatile compounds found in the coconut shell liquid smoke.
Simulation and Experimental Study of a 2D Photonic Crystal Structure that Reflects a Quantum Dots Emission in the Normal Direction Isnaeni,; Cho, Yong Hoon
Makara Journal of Science Vol. 20, No. 3
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Abstract

Two-dimensional photonic crystal structures not only confine light and guide waves laterally but also reflect light in the normal direction due to a slow Bloch mode effect. However, evidence of the utilization of this structure as a mirror is required. Therefore, in this work, a simulation was made and experimental results were obtained to prove that there was an increase in the intensity of reflected CdSe colloidal quantum dots emission in the normal direction when a 2D photonic crystal structure was used. A thin TiO2 film was shaped into a two-dimensional photonic crystal structure using a simple sol-gel and polystyrene-mask-etching procedure. This structure was then placed on top of the thin CdSe quantum dots film layer. The emission of quantum dots onto the two-dimensional photonic crystal structure was compared to quantum dots emission onto a flat, thin TiO2 film. An increase in the quantum dots emission of up to 105% was in the presence of the two-dimensional photonic crystal structure. This finding is very useful for photonic device applications, such as light-emitting diodes, laser systems and bio-tagging detection systems.
Determination of Pathotypes from Indonesian Xanthomonas oryzae Pv. Oryzae Population causing Bacterial Leaf Blight and their Reactions on Differential Rice Suryadi, Yadi; Samudra, I Made; Priyatno, Tri Puji; Susilowati, Dwi Ningsih; Lestari, Puji; Fatimah,; Kadir, Trini Suryani
Makara Journal of Science Vol. 20, No. 3
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Abstract

The objective of this work was to study the virulence of 15 Xanthomonas oryzae pv. oryzae (Xoo) isolates collected in three provinces in Indonesia (North Sumatra, South Sumatra, and South Sulawesi) based on five Indonesian differential rice genotypes and 10 near isogenic lines (NILs) that have been known to differ in their resistance to bacterial leaf blight (BLB), in a greenhouse assessment. In addition, this study also aims to monitor the responses of 31 rice genotypes (21 NILs, five differentials, five improved cultivars) to BLB disease in a field experiment. The 15 isolates showed different virulence patterns on the NILs’genotypes with a single resistance gene indicating the pathogen diversity. Eight different pathotypes were present, as demonstrated by a particular virulence pattern of each isolate on the genotypes. Determination of Xoo pathotype revealed that Xoo pathotypes responded differently based on their reaction to NILs and Indonesian differential genotypes. The field assessment demonstrated the incidence and severity of BLB disease on rice genotypes ranging from 25% to 100% and 5.5% to 72.91%, respectively, while the mean disease index ranged from 1.15% to 72.9%. The disease response varied among rice genotypes. IRBB50 (Xa4+xa5), IRBB51 (Xa4+xa13), IRBB52 (Xa4+Xa21), IRBB53 (Xa4+Xa21), IRBB56 (Xa4+xa5+xa13), IRBB57 (Xa4+xa5+Xa21), IRBB59 (Xa4+xa13+Xa21), IRBB64 (Xa4+xa5+Xa7+Xa21), IRBB66 (Xa4+xa5+Xa7+xa13+Xa21), IRBB7(Xa7), Angke (Xa4+xa5) and Code (Xa4+Xa7) were revealed to be highly resistant to the BLB pathogen. These genotypes have potential as genetic material for the pyramiding of several resistance genes for the development of rice resistance to BLB disease in Indonesia.
Extraction of the Proton Charge Radius from Experiments Kelkar, Neelima Govind; Mart, Terry; Nowakowski, Marek
Makara Journal of Science Vol. 20, No. 3
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Abstract

The static properties of hadrons, such as their radii and other moments of the electric and magnetic distributions, can only be extracted using theoretical methods and cannot be directly measured from experiments. As a result, discrepancies between the extracted values from different precision measurements can exist. The proton charge radius, rp, which is extracted either from electron-proton (e-p) elastic scattering data or from hydrogen atom spectroscopy, seems to be no exception. The value rp = 0.84087(39) fm extracted from muonic hydrogen spectroscopy is about 4% smaller than that obtained from e-p scattering or standard hydrogen spectroscopy. The resolution of this so-called proton radius puzzle has been attempted in many different ways over the past six years. The present article reviews these attempts with a focus on the methods of extracting the radius.
Identification of MADS-box Gene in Oil Palm (Elaeis guineensis Jacq.) Nawfetrias, Winda; Sobir,; Faizal, Irvan
Makara Journal of Science Vol. 20, No. 3
Publisher : UI Scholars Hub

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Abstract

The bunch size represented by the fruit number is the main parameter of oil palm (Elaeis guineensis Jacq.) yield. The fruit number, which is determined during the initial phase of development, is related to various factors, including the genetic properties of the trees. Trees that have more pistillate flowers have more fruit. The diversity of MADS-box genes assumed can be used as a marker for trees that have a higher number of pistillate flowers. Therefore, the aims of this research were to isolate and identify the MADS-box genes from flowers of tenera oil palm using PCR techniques. The SQUAMOSA (SQUA) gene and the GLOBOSA (GLO) gene are members of the MADS-box genes family that are responsible for sepal, petal and stamen organ development. The genomic DNA of the staminate flowers of trees that have more staminate flowers (P1) and the genomic DNA of the pistillate flowers of trees that have more pistillate flowers (P2) were isolated using the CTAB+ PVP method. The CTAB+PVP method was more efficient for isolating pistillate flower genomic DNA than staminate flower genomic DNA. The genomic DNA of P1 and P2 was amplified with two primers: BMS and BMG. The BMS primers gave a PCR product size of 1250 bp for the genomic DNA of P1 and P2. Meanwhile, the BMG primers gave a PCR product size of 1250 bp and 1300 bp for P1 and P2, respectively. The PCR products were sequenced and analyzed for homology using the GenBank database. BLAST analysis showed the PCR products have high homology with the SQUA1 gene and the GLO2 gene. Alignment analysis showed that the DNA fragments amplified with the BMS primers of the P1 and P2 sequences have variations in the exons and introns, and the variations were observed only in the introns of the DNA fragments amplified with the BMG primers.
Atomic Ensemble Effects and Non-Covalent Interactions at the Electrode–Electrolyte Interface Cuesta, Angel
Makara Journal of Science Vol. 20, No. 3
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Abstract

Cyanide-modified Pt(111) electrodes have been recently employed to study atomic ensemble effects in electrocatalysis. This work, which will be briefly reviewed, reveals that the smallest site required for methanol dehydrogenation and formic acid dehydration is composed of three contiguous Pt atoms. By blocking these trigonal sites, the specific adsorption of anions, such as sulfate and phosphate, can be inhibited, thus increasing the rate of oxygen reduction reaction by one order of magnitude or more. Moreover, alkali metal cations affect hydrogen adsorption on cyanide-modified Pt(111). This effect is attributed to the non-covalent interactions at the electrical double layer between specifically adsorbed anions or dipoles and the alkali metal cations. A systematic investigation is conducted on the effect of the concentration of alkali metal cations. Accordingly, a simple model that reproduces the experimental observations accurately and enables the understanding of the trends in the strength of the interaction between M+ and CNad when moving from Li+ to Cs+, as well as the deviations from the expected trends, is developed. This simple model can also explain the occurrence of super-Nernstian shifts of the equilibrium potential of interfacial proton-coupled electron transfers. Therefore, the model can be generally applied to explain quantitatively the effect of cations on the properties of the electrical double layer. The recently reported effects of alkali metal cations on several electrocatalytic reactions must be mediated by the interaction between these cations and chemisorbed species. As these interactions seem to be adequately and quantitatively described by our model, we expect the model to also be useful to describe, explain, and potentially exploit these effects.
Estimation of Raindrop Size Distribution Parameters Using Rain Attenuation Data from a Ku-Band Communications Satellite Indrayani, Wira; Marzuki,; Vonnisa, Mutya
Makara Journal of Science Vol. 20, No. 3
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Abstract

The rain attenuation of down-link radio wave signals from the Superbird-C satellite and surface rainfall data have been used to estimate the parameters of exponential raindrop size distribution (DSD) at Koto Tabang (100.32 °E, 0.20 °S), West Sumatra, Indonesia. Prior to analyzing the measured data, the ability of the method to recover the parameters of known DSDs from which the samples were taken was examined. It was found that the method can accurately retrieve the input parameter of the sample. Only six case studies are presented here, so the results are representative rather than definitive. The method successfully estimated the DSD parameters of a stratiform case with steady intensity and deep convective rains of a short duration. This can be inferred from the small difference between the parameters derived from rain attenuation data and those derived from a 2D video disdrometer. The poor performance of the method was observed for a stratiform case with strong rain intensity fluctuation and shallow convective rains with very low rain top height. This phenomenon is probably due to the bias that may be inherent in the estimation of specific rain attenuation, such as the assumption of a constant path length throughout the rain.

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