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Journal of Mathematical and Fundamental Sciences
Published by Institut Teknologi Bandung
ISSN : 23375760     EISSN : 23385510     DOI : https://doi.org/10.5614/j.math.fund.sci.
Core Subject : Science, Education,
Astronomy Chemistry Earth & Planetary Sciences Mathematics Physics
Journal of Mathematical and Fundamental Sciences welcomes full research articles in the area of Mathematics and Natural Sciences from the following subject areas: Astronomy, Chemistry, Earth Sciences (Geodesy, Geology, Geophysics, Oceanography, Meteorology), Life Sciences (Agriculture, Biochemistry, Biology, Health, Medical, Pharmacy), Mathematics, Physics, and Statistics.
Arjuna Subject : Matematika - Matematika (Lain-Lain)
Articles 9 Documents
 1 
Search results for , issue "Vol. 47 No. 3 (2015)" : 9 Documents clear
QuEChERS Method for the Determination of Pesticide Residues in Indonesian Green Coffee Beans using Liquid Chromatography Tandem Mass Spectrometry Harmoko Harmoko; Rahmana Emran Kartasasmita; Astika Tresnawati
Journal of Mathematical and Fundamental Sciences Vol. 47 No. 3 (2015)
Publisher : Institute for Research and Community Services (LPPM) ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.math.fund.sci.2015.47.3.7

Abstract

A method using QuEChERS sample preparation followed by liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESIMS/MS) was developed for quantitative determination of 14 pesticide residues in Indonesian green coffee beans. The European Standard Method EN 15662:2008 was modified to obtain an appropriate extraction and clean-up procedure for green coffee bean samples. Homogenous slurry samples were extracted with 1% acetic acid in acetonitrile and the extracts were cleaned up by a high pigment dispersive SPE. LC-ESI-MS/MS was operated in the MRM mode for two specific precursor-product ion transitions per target compound to obtain 4 identification points. Representative matrix-matched calibration curves were applied to compensate matrix effects. This method was validated according to the requirements of SANCO/12495/2011. Limits of detection (LODs) and limits of quantification (LOQs) were obtained in the ranges of 0.2-2.9 μg kg-1 and 0.8-9.7 μg kg-1 respectively, showing lower values than the maximum residu limits (MRLs) set by importing countries. The method was applied to determine 14 pesticide residues in 181 Indonesian green coffee bean samples that were taken from different regions. Some pesticide residues were found in these samples and detected to be higher than the MRLs.
Simple and Low-Cost On-Package Sticker Sensor based on Litmus Paper for Real-Time Monitoring of Beef Freshness Bambang Kuswandi; Fitria Damayanti; Jayus Jayus; Aminah Abdullah; Lee Yook Heng
Journal of Mathematical and Fundamental Sciences Vol. 47 No. 3 (2015)
Publisher : Institute for Research and Community Services (LPPM) ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.math.fund.sci.2015.47.3.2

Abstract

A simple sticker sensor has been constructed using litmus paper and tests have been conducted to detect the freshness of beef samples. The results show that the sticker sensor can be used to determine the degree of beef freshness, since the color change of the litmus paper and the quality degradation of the beef during storage time had a similar trend, where the decay of the beef could be detected clearly (when the red litmus paper changed to blue). The sticker sensor reacted accurately to the beef's freshness in terms of pH change due to beef deterioration from pH 5.61 to 6.24 and from pH 5.67 to 6.02 as shown by its color change in real time at room and chiller temperature respectively. Thus, the sticker sensor can be used as an effective tool for monitoring the microbial quality of packaged fresh meat that correlates with the increased pH of the beef, where the total viable count (TVC) of 5 x 106 cfu/g or 6.698 log cfu/g correlates with a pH of 6.24. These levels were reached at 10 hrs and 7 days at room and chiller temperature respectively. This study provides a foundation for developing a simple sensor for beef freshness.
Some Basic Properties of Completely Prime Ideals in Near Rings Pairote Yiarayong
Journal of Mathematical and Fundamental Sciences Vol. 47 No. 3 (2015)
Publisher : Institute for Research and Community Services (LPPM) ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.math.fund.sci.2015.47.3.1

Abstract

In this investigation we studied completely prime, weakly completely prime, quasi completely prime and weakly quasi completely prime ideals in near-rings. Some characterizations of completely prime and weakly completely prime ideals were obtained. Moreover, we investigated relationships between completely prime and weakly completely prime ideals in near-rings. Finally, we obtained necessary and sufficient conditions for a weakly completely prime ideal to be a completely prime ideal.
Pb-free Radiation Shielding Glass Using Coal Fly Ash Watcharin Rachniyom; Suparat Tuscharoen; Jakrapong Kaewkhao; Pumipat Pachana
Journal of Mathematical and Fundamental Sciences Vol. 47 No. 3 (2015)
Publisher : Institute for Research and Community Services (LPPM) ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.math.fund.sci.2015.47.3.8

Abstract

In this work, Pb-free shielding glass samples were prepared by themelt quenching technique using subbituminous fly ash (SFA) composed ofxBi2O3 : (60-x)B2O3 : 10Na2O : 30SFA (where x = 10, 15, 20, 25, 30 and 35 by wt%). The samples were investigated for their physical and radiation shielding properties. The density and hardness were measured. The results showed that the density increased with the increase of Bi2O3 content. The highest value of hardness was observed for glass sample with 30 wt% of Bi2O3 concentration. The samples were investigated under 662 keV gamma ray and the results were compared with theoretical calculations. The values of the mass attenuation coefficient (μm), the atomic cross section (σe) and the effective atomic number (Zeff) were found to increase with an increase of the Bi2O3 concentration and were in good agreement with the theoretical calculations. The best results for the half-value layer (HVL) were observed in the sample with 35 wt% of Bi2O3 concentration, better than the values of barite concrete. These results demonstrate the viability of using coal fly ash waste for radiation shielding glass without PbO in the glass matrices.
Quasi-2D Resistivity Model from Inversion of Vertical Electrical Sounding (VES) Data using Guided Random Search Algorithm Diky Irawan; Hendra Grandis; Prihadi Sumintadiredja
Journal of Mathematical and Fundamental Sciences Vol. 47 No. 3 (2015)
Publisher : Institute for Research and Community Services (LPPM) ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.math.fund.sci.2015.47.3.5

Abstract

Vertical electrical sounding (VES) data are usually interpreted in terms of a 1D resistivity model using linearized inversion. The local approach of a non-linear inverse problem has fundamental limitations, i.e. the necessity of a starting model close to the solution and possible convergence to a local rather than a global minimum solution. We studied the application of a global search approach for non-linear inversion using the guided random search method to model VES data. A quasi-2D resistivity model can be created by stitching 1D models obtained from VES data along a profile. Both vertical and lateral resistivity variations are minimized to incorporate a 2D smoothness constraint. The proposed method was applied to invert synthetic VES data as well as field data from a sedimentary environment. Both synthetic and field data inversions resulted in models that correlated well with the known synthetic model and with the geology of the study area, respectively.
On The Total Irregularity Strength of Regular Graphs Rismawati Ramdani; A.N.M. Salman; Hilda Assiyatun
Journal of Mathematical and Fundamental Sciences Vol. 47 No. 3 (2015)
Publisher : Institute for Research and Community Services (LPPM) ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.math.fund.sci.2015.47.3.6

Abstract

Let 𝐺 = (𝑉, 𝐸) be a graph. A total labeling 𝑓: 𝑉 ∪ 𝐸 → {1, 2, ⋯ , 𝑘} iscalled a totally irregular total 𝑘-labeling of 𝐺 if every two distinct vertices 𝑥 and𝑦 in 𝑉 satisfy 𝑤𝑓(𝑥) ≠ 𝑤𝑓(𝑦) and every two distinct edges 𝑥1𝑥2 and 𝑦1𝑦2 in 𝐸satisfy 𝑤𝑓(𝑥1𝑥2) ≠ 𝑤𝑓(𝑦1𝑦2), where 𝑤𝑓(𝑥) = 𝑓(𝑥) + Σ𝑥𝑧∈𝐸(𝐺) 𝑓(𝑥𝑧) and𝑤𝑓(𝑥1𝑥2) = 𝑓(𝑥1) + 𝑓(𝑥1𝑥2) + 𝑓(𝑥2). The minimum 𝑘 for which a graph 𝐺 hasa totally irregular total 𝑘-labeling is called the total irregularity strength of 𝐺,denoted by 𝑡𝑠(𝐺). In this paper, we consider an upper bound on the totalirregularity strength of 𝑚 copies of a regular graph. Besides that, we give a dual labeling of a totally irregular total 𝑘-labeling of a regular graph and we consider the total irregularity strength of 𝑚 copies of a path on two vertices, 𝑚 copies of a cycle, and 𝑚 copies of a prism 𝐶𝑛 □ 𝑃2.
Embryo Incision as a New Technique for Double Seedling Production of Indonesian Elite Coconut Type “Kopyor” Sisunandar Sisunandar; Alkhikmah Alkhikmah; Arief Husin; Aman Suyadi
Journal of Mathematical and Fundamental Sciences Vol. 47 No. 3 (2015)
Publisher : Institute for Research and Community Services (LPPM) ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.math.fund.sci.2015.47.3.3

Abstract

One of the present major limitations of seedling production of kopyor type coconut using embryo culture is that only one seedling can be produced from a single embryo. Therefore, we report on the development of a new breakthrough technique for the production of double seedlings from a single embryo. The technique consists of four steps, viz. (i) germination; (ii) incision; (iii) splitting; and (iv) recovery. A histological study was carried out on the development of the halved embryo into a new shoot. The best recovery process was obtained when the incised embryo was split into two and recovered into Murashige and Skoog (MS) medium supplemented with 2 μM IBA and 15 μM kinetin. Following this protocol, an average of 56 shoots was successfully recovered from 30 zygotic embryos. The histological study also revealed that the meristem tissue of the halved embryo was able to produce a new meristem and primordial leaf. Most of the shoots then went on to produce normal seedlings and could be acclimatized successfully after having developed 2 or 3 leaves. This protocol is useful for routine seedling production of the kopyor-type coconut.
The Potency of Trigona’s Propolis Extract as Reactive Oxygen Species Inhibitor in Diabetic Mice Ahmad Ridwan; Ayu Nirmala Sari; Ramadhani Eka Putra
Journal of Mathematical and Fundamental Sciences Vol. 47 No. 3 (2015)
Publisher : Institute for Research and Community Services (LPPM) ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.math.fund.sci.2015.47.3.4

Abstract

Hyperglycemia has been proven to increase oxidative stress due to the production of reactive oxygen species (ROS) that exceed the capabilities of the natural antioxidant defenses, causing a deficiency in insulin receptors and insulin resistance. In this study, the effect of propolis on ROS was observed. Fifty five (55) male mice (Mus musculus SW.) were divided into 5 groups, i.e. KN (normal control), KDM (diabetes control), and P1, P2, P3. Propolis solution 50, 100 and 175 mg/kg bw was given to groups P1, P2 and P3 respectively, while distilled water was given to groups KN and KDM by oral gavage for 21 days. Density of ROS was measured every 7 days, while measurement of plasma insulin was carried out every 3 days. The results show that the density of ROS in the groups treated with propolis was lower than in the KDM group. However, the plasma insulin levels in the propolis groups were higher than in the KDM group. It was concluded that propolis can decrease ROS density and causes an increase in plasma insulin levels.
Cover Vol. 47 No. 3, 2015 Journal of Mathematical and Fundamental Sciences
Journal of Mathematical and Fundamental Sciences Vol. 47 No. 3 (2015)
Publisher : Institute for Research and Community Services (LPPM) ITB

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