https://ejournal.um.edu.my/index.php/MJS/issue/feed Malaysian Journal of Science 2022-03-07T15:56:23+08:00 Editor-in-Chief / Journal Manager mjs_um@um.edu.my Open Journal Systems <p style="text-align: justify;">Malaysian Journal of Science (MJS), launched in 1972, is the official peer-reviewed open access journal of the&nbsp;<a href="https://fs.um.edu.my/">Faculty of Science, University of Malaya</a>.&nbsp;Effective from&nbsp;year 2020 onwards, the frequency of regular issues publication is&nbsp;three&nbsp;times a&nbsp;year; on&nbsp;every February, June and October. MJS is indexed in Scopus, EMBASE, Compendex, GEOBASE, EMBiology, Elsevier BIOBASE, FLUIDEX ,World Textiles, CAB Abstracts, Chemical Abstracts Service Database and ASEAN Citation Index (ACI).</p> <p style="text-align: justify;">MJS is a reputable journal with a growing number of audience, which focuses on current developments in all disciplines of science. The journal publishes original articles, review articles, short communications and case reports that are of importance to the scientific community.&nbsp;</p> <p style="text-align: justify;"><strong>eISSN&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;: 2600-8688<br></strong><strong><strong>Print ISSN&nbsp; &nbsp;: 1394-3065<br></strong></strong><strong><strong>Publisher&nbsp; &nbsp; : Faculty of Science, University of Malaya</strong></strong>&nbsp;</p> https://ejournal.um.edu.my/index.php/MJS/article/view/27448 RAINWATER HARVESTING SYSTEM’S UTILIZATION FOR DOMESTIC WATER NEEDS IN KOBANGO II HAMLET, BANTUL REGENCY 2021-04-20T16:45:19+08:00 Dian Hudawan Santoso dian.hudawan@upnyk.ac.id Berty Dwi Rahmawati berty.dr@upnyk.ac.id <p>Limited groundwater, especially during the dry season, poses a challenge for Kobango II Hamlet Bantul Regency residents to have sufficient clean water supply for their daily needs. Inadequate aquifer conditions and the inability to release enough water are reasons for clean water scarcity. Thus, this study aims to determine the effectiveness of using the rainwater harvesting (RWH) system for domestic water needs in the Kobango II Hamlet Bantul Regency. The method used in this research is conducting a survey, observation, quantitative analysis of secondary data using rainfall data and aquifer conditions and calculating RWH system requirements. The results obtained from this research demonstrated that the required diameter of the vertical gutter for the RWH system is 6.65 cm and the diameter of the gutter is 0.056 cm.</p> 2022-03-07T00:00:00+08:00 Copyright (c) 2022 Malaysian Journal of Science https://ejournal.um.edu.my/index.php/MJS/article/view/29117 HORSESHOE CRAB AND ITS SPAWNING GROUND CONDITION IN JOHOR LAMA, JOHOR 2021-05-21T09:44:44+08:00 Mohd Razali Md Razak razalirazak5379@gmail.com Zaleha Kassim drzack@iium.edu.my Ridhwan Abd Wahab ridhwan@iium.edu.my Noor Yuslida Hazahari noory@iium.edu.my <p>This study was conducted at horseshoe crab’s natural spawning ground in Johor Lama, Kota Tinggi, Johor, Malaysia (1°35'00"N 104°00'49"E). Six nests were excavated on 4 August 2020, four hours after the highest tide. Conditions of the spawning site were observed and recorded. Grain size analysis was conducted. Eggs hatching rate, larvae moulting rate, infection rate, and larvae abnormality rate were recorded. There are two types of reclamation observed in Johor Lama: (i) concrete wall and (ii) stack of boulders. Mangrove and muddy areas in Johor Lama are still preserved and in good condition. Sand in the horseshoe crab spawning beach in Johor Lama was coarser and poorly sorted ( : 0.09± 0.01 cm; : 1.89 ± 0.03) as compared to the one in Balok, Pahang (mid-tide mark, August 2012: : 2.38 ± 0.04 cm; : 0.86 ± 0.04). The quantity of the eggs inside each nest in Johor Lama was also in accordance with the other previous studies (first nest n: 256, second nest n: 229, third nest n: 132, fourth nest n: 123, fifth nest n: 149, sixth nest n: 134). However, the hatching rates of each sample in this population were observed to be lower than the others previously studied (31.8% – 66.1%). Two types of larvae abnormalities were reported in this study: (i) genetic impairment that changed the basic Xiphosura’s body plan and (ii) external factor that caused by the impact of the substrate or predatory action that would distort the shape of the juvenile exoskeleton. Based on the observation, the natural ecosystem in Johor Lama is still in good preservation, since it is far from urbanisation and has less deforestation. However, the future of this spawning site is still in doubt, since many ports and industrials zones are located on the opposite side of the river in Johor Bahru district that could lead to the worst water pollution.</p> 2022-02-28T00:00:00+08:00 Copyright (c) 2022 Malaysian Journal of Science https://ejournal.um.edu.my/index.php/MJS/article/view/27622 EFFECT OF OUTSOLE THICKNESS ON RUNNING BIOMECHANICS 2021-08-10T14:36:06+08:00 Chan Siow Cheng chansc@utar.edu.my Koh Wei Lin felisekoh@1utar.my Tan Yin Qing tanyq@utar.edu.my <p>Running shoes with increased or decreased sole thickness are postulated to improve running performance, besides to protect runners against high impact forces and running injuries. However, there is no evidence showing that running shoe developments emerging on the market help tackle running injuries. In this study, we compared the effect of different outsole thicknesses: (i) barefoot, (ii) minimalist and (iii) maximalist sports shoes on running biomechanics. Fifteen male subjects (age 23.19 ± 0.73 years old) who had regular exercises for at least 75 minutes per week were recruited to participate in this study. Participants had completed three minutes of running on a treadmill in each condition. Lower extremity kinetics and kinematics were analysed. There was no difference between maximalist running shoes and minimalist running shoes with respect to maximum vertical ground reaction force (VGRF) (<em>p</em> = 0.221), step length (<em>p</em> = 0.50) and cadence (<em>p</em> = 0.30). In addition, we observed longer ground contact time in maximalist running shoes (1.087 ± 0.115 s) when compared with minimalist running shoes (1.051 ± 0.105 s) (<em>p</em> = 0.007). On the other hand, runners had significantly higher knee flexion and adduction in minimalist shoes than maximalist shoes (<em>p</em> = 0.046). In conclusion, running in minimalist shoes, at least in a short period, produces greater running efficiency with shorter ground contact time but may result in a higher injury risk at the knee joint.</p> 2022-02-28T00:00:00+08:00 Copyright (c) 2022 Malaysian Journal of Science https://ejournal.um.edu.my/index.php/MJS/article/view/23084 ASSESSMENT OF SEDIMENT REPLENISHMENT VOLUME IN LANGAT RIVER SYSTEM 2020-12-08T15:53:09+08:00 Nur Hidayah Huqmah Mahmud hidayahuqmah@gmail.com Nor Rohaizah Jamil norrohaizah@upm.edu.my Ahmad Fikri Abdullah ahmadfikri@upm.edu.my Mohd Sofiyan Sulaiman sofiyan@umt.edu.my <p>The river sand mining activity has taken place in a sand-bed river system in Selangor, Malaysia for decades even before the legalisation was initiated in 2008. This study focuses on the determination of optimum sand extraction for low-flow and high-flow seasons. The sand replenishment rate was used as the benchmark in determining the threshold level of the extractable rate in the Langat River, Selangor system. The total sediment load was computed using Yang (1973) equation due to the high percentage of agreement between the predicted sediment load and measured sediment load. Almost 41.6% of the predicted data fall within the allowable discrepancy ratio test between the predicted value and measured value. The comparison of sand replenishment rate in high and low flow seasons proved that the river system has quicker capabilities in sand replenishment rate at the extraction point during the high-flow season compared to the latter by 83%. The quantifiable volume of the extractable sand rate is proposed specifically during low-flow months (May to September) whereby the slower replenishment rate is critical and riskier. The optimal sand mining volume during the low-flow months is calculated by reducing 10% from the total replenishment volume and the recommended optimum extraction load has been delivered by the number of 25 tons lorries for easier observation by the contractor and authority’s body. The monthly optimum extraction in Langat River during low-flow months is calculated at a minimum of 437 trucks to a maximum of 20,114 trucks per month.</p> 2022-02-28T00:00:00+08:00 Copyright (c) 2022 Malaysian Journal of Science https://ejournal.um.edu.my/index.php/MJS/article/view/26122 MEASUREMENT OF IRON, MANGANESE, COPPER, COBALT AND LEAD TO ASSESS THE EDIBLE FITNESS OF M. CEPHALUS COLLECTED FROM LASBELA (BALOCHISTAN), PAKISTAN, USING ATOMIC ABSORPTION SPECTROSCOPY 2021-01-26T17:23:32+08:00 Fehmeeda Afzal fahmeedaafzal22@gmail.com Sami ullah sami435889@gmail.com Ashraf Nadeem ashrafbaluch@gmail.com Muhammad Aslam aslambc@hotmail.com Muhammad Shafi drmshafi3333@hotmail.com Khalil Hasni khalil_hasni1@yahoo.com Abdul Hakeem a.hakeem.faeem@gmail.com Sonia Tariq tariq.sonia@ymail.com <p>The sea serves as a good source of food. The direct discharge of pollutants into aquatic environments can result in exceeded levels of heavy metals. This can harm the organisms and cause serious health issues when consumed by humans. <em>Mugil cephalus </em>is consumed as food, and its continuous analysis for heavy metals is required for food safety. Some selected metals – namely iron, copper, manganese, cobalt and lead – were evaluated in muscle tissues of <em>Mugil cephalus</em> collected from two major fish landing sites (i.e. Gaddani and Damb) along the Lasbela coast of Balochistan). The concentration of metals was determined using an atomic absorption spectrometer. For this purpose, several digestion methods were used to digest the meat for comparison. Using H<sub>2</sub>SO<sub>4</sub>, HNO<sub>3</sub> and HClO<sub>4 </sub>was the most effective method, which is an important analytical finding for future researchers to consider. The concentrations of metals assumed the order of Fe &gt; Cu &gt; Pb &gt; Mn &gt; Co in samples from Gaddani and Fe &gt; Cu &gt; Mn &gt; Pb &gt; Co in samples taken from Damb. Among the metals analyzed, iron levels at Gaddani and Damb were found within the permissible values suggested by the World Health Organization (WHO), Food and Agriculture Organization (FAO), and United States Environmental Protection Agency (USEPA). Copper and lead levels were higher than the safe limits in samples from both sites. The estimated daily and weekly metals intake in an average 70 kg person were lower than the limits proposed by the FAO and WHO for all metals. The overall results revealed that the selected fish species is safe for consumption and presents no hazardous effects on human health. However, Gaddani fish Harbor and Damb should be protected from the direct discharge of pollutants, and the future monitoring of <em>M. cephalus</em> fish is required to make sure the edible meat is safe for consumption.</p> 2022-02-28T00:00:00+08:00 Copyright (c) 2022 Malaysian Journal of Science https://ejournal.um.edu.my/index.php/MJS/article/view/32933 STUDYING THE EFFECT OF SOLAR ACTIVITIES ON THUNDERSTORMS IN IRAQ FOR SOLAR-CYCLES 23 & 24 2021-12-09T10:05:47+08:00 Mohammed Ramadan Mohammed.scp102@student.uomosul.edu.iq Imad Hussain dr.imad1972@uomosul.edu.iq <p>Studying the impact of solar activity on the Earth's climate is significant for predicting the change of its elements for long periods. Most studies have focused on the relationship between sunspots and changes in one of the climate elements. In this research, the effect of the solar activities that consist of coronal mass ejections and solar flare, and the sunspots number on thunderstorms that occur during the winter season in Iraq for the period from (1996-2019) representing the Solar-Cycles 23 &amp; 24, respectively, were investigated in this study. In general, the statistical results show that, the monthly average increase for each of the following: energies of coronal mass ejections, solar flares, and the sunspots number, the monthly frequency of thunderstorms decreases. The Solar-Cycle 24 is the weakest among the cycles of the last century; therefore, its results were not precise.</p> 2022-03-07T00:00:00+08:00 Copyright (c) 2022 Malaysian Journal of Science https://ejournal.um.edu.my/index.php/MJS/article/view/29058 SYNTHESIS, CHARACTERIZATION, IN SILICO OPTIMIZATION, AND CONFORMATIONAL STUDIES OF METHYL 4-O-PIVALOYL-α-L-RHAMNOPYRANOSIDES 2021-07-23T23:12:50+08:00 Mohammed Mahbubul Matin mahbubchem@cu.ac.bd Mohammad Ibrahim mibrahim2007cu@gmail.com Tasnim Rahman Anisa tani72761@gmail.com Md. Rezaur Rahman rmrezaur@unimas.my <p>Considering promising biological activities of natural and synthetic rhamnopyranoside esters, we have synthesized several methyl 4-<em>O</em>-pivaloyl-α-L-rhamnopyranosides <em>via</em> selective 2,3-<em>O</em>-acetonide protection of methyl α-L-rhamnopyranoside (<strong>4</strong>) followed by C-4 pivaloylation, and deprotection. The synthesized 4-<em>O</em>-pivaloate <strong>7</strong> and its 2,3-di-<em>O</em>-esters <strong>8a-e</strong> are characterized by spectroscopy and are optimized by using density functional theory (DFT). The free energy and bond angles thus calculated are used to establish the probable conformation(s). The 2,3-<em>O</em>-acetonide protected rhamnopyranosides <strong>5</strong>-<strong>6</strong> are found to be slightly distorted from the regular <sup>1</sup><em>C</em><sub>4</sub> conformation, and exist between the chair and twist-boat (skew) conformation while other pivaloyl esters <strong>7</strong>-<strong>8a-e</strong> exist in regular <sup>1</sup><em>C</em><sub>4</sub> chair conformation.</p> 2022-03-07T00:00:00+08:00 Copyright (c) 2022 Malaysian Journal of Science https://ejournal.um.edu.my/index.php/MJS/article/view/31753 INFRARED SPECTRAL AND MAGNETIC PROPERTIES OF BASIC COPPER(II) NITRATE PRODUCED BY SLOW TITRATION METHOD 2021-11-26T15:10:04+08:00 Regina Tutik Padmaningrum regina_tutikp@uny.ac.id Isana Supiah Yosephine Louise isana_supiah@uny.ac.id Isti Yunita isana_supiah@uny.ac.id Kristian Handoyo Sugiyarto sugiyarto@uny.ac.id <p>The main purposes for this work are to formulate and characterize the infrared (IR) and magnetic moment of the compounds resulted from the slow titration of copper(II) nitrate with sodium hydroxide and in the reverse procedures in an aqueous solution. The titration is carried out with various concentrations and at a constant temperature, ⁓ 19 <sup>o</sup>C, and monitored using <em>p</em>H meter with the rate of the titration⁓ 1 mL per minute. The corresponding data of change in mole ratio of Cu<sup>2+</sup>/OH<sup>-</sup> against <em>p</em>H reveals that the end point of the titration occurs at <em>p</em>H about 8, leading to stoichiometry formula, 3Cu(NO<sub>3</sub>)<sub>2</sub>.5Cu(OH)<sub>2</sub>, but Cu(NO<sub>3</sub>)<sub>2</sub>.5Cu(OH)<sub>2 </sub>in the reverse procedure (OH<sup>-</sup>/Cu<sup>2+</sup>). The pale blue for the former but deep blue compounds were isolated and then characterized IR spectroscopy and magnetic moment. Both compounds containing nitrate ion are evident from the corresponding IR spectra, and their magnetic moment values which were found in the range of 1.7-1.9 BM, are to be normal for copper(II) salt corresponding to one unpaired electron in the electronic configuration.</p> 2022-03-07T00:00:00+08:00 Copyright (c) 2022 Malaysian Journal of Science