Browse publications by year: 2018

  1. Julie Elvyana Romli, Norhamidi Muhamad, Abu Bakar Sulong, Farhana Mohd Foudzi, Nor Nabilla Kadiman
    Sains Malaysiana, 2018;47:1039-1043.
    Kajian mengenai grafin kini semakin meluas disebabkan sifat kebolehaliran terma yang mampu meningkatkan potensi
    bahan komposit. Penambahan grafin dalam matriks kuprum dikaji dengan menggunakan gabungan bahan pengikat
    iaitu polietilena glikol (PEG), polimetil metakrilat (PMMA) dan asid stearik. Penggunaan grafin sebagai bahan pengisi
    dalam matriks kuprum merupakan pendekatan baru yang bertujuan untuk meningkatkan kebolehaliran terma produk
    yang dihasilkan. Namun, penambahan grafin dalam matriks kuprum boleh menyebabkan ketidaksamarataan zarah
    komposit kerana penggumpalan zarah-zarah grafin. Oleh itu, kaedah sonikasi dan pengacauan magnetik semasa proses
    pra-campuran digunakan bagi menghasilkan bahan suapan yang sebati dan penyerakan grafin yang lebih baik tanpa
    penggumpalan. Suhu proses sonikasi telah ditetapkan pada 55˚C dengan masa sonikasi yang berbeza iaitu 30 minit, 60
    minit dan 90 minit. Bagi proses pengacauan magnetik, parameter yang digunakan adalah 55˚C, selama 21 jam pada
    kelajuan yang berbeza iaitu 300, 350 dan 400 rpm. Analisis imej Pancaran Medan Mikroskopi Elektron Pengimbasan
    (FESEM) dan Pemetaan EDX telah dijalankan bagi mengkaji penyerakan grafin dalam komposit kuprum grafin. Keputusan
    menunjukkan hasil yang lebih baik diperoleh selepas proses sonikasi dan pengacauan magnetik dijalankan. Penyerakan
    terbaik yang lebih seragam dan sebati diperoleh pada masa sonikasi 60 min dan pengacauan magnetik pada kelajuan
    sederhana iaitu 350 rpm. Zarah grafin didapati kurang bertumpu pada satu tempat dan penggumpalan semula juga
    tidak berlaku. Penyerakan sebati ini menjadikan hubungan antara muka zarah-zarah grafin dan kuprum menjadi lebih
    baik seterusnya mampu mengurangkan keliangan bagi penghasilan jasad akhir.
  2. Nur Akmar Jamil, Gan SM, Burhanuddin Yeop Majlis, Susthitha Menon P
    Sains Malaysiana, 2018;47:1033-1038.
    Artikel ini menganalisis biosensor resonans plasmon permukaan (SPR) dengan lapisan grafin yang meningkatkan
    kecekapan biosensor urea kerana penerapannya yang tinggi. Tatasusunan Kretschmann merupakan teknik yang paling
    berkesan digunakan untuk pengujaan plasmon. Dalam kajian ini, kami menganalisis kesan ekalapisan MoS2 dengan
    lapisan grafin yang didepositkan pada bahan plasmon, iaitu logam emas (Au), di dalam tatasusunan ini. Simulasi untuk
    menganalisis tatasusunan ini adalah berdasarkan kepada kaedah perbezaan terhingga domain masa (FDTD). Prestasi
    biosensor SPR dapat dipantau dengan menganalisis kepekaan dan lebar penuh pada separuh maksimum (FWHM) spektrum
    SPR. Pengukuran diperhatikan pada panjang gelombang 670 nm dan 785 nm untuk pengesanan urea. Indeks molar dan
    indeks biasan berbeza (RI) daripada 1.335 sehingga 1.342 untuk lapisan penderiaan. Keputusan menunjukkan peratus
    peningkatan kepekaan biosensor Au/MoS2
    /grafin berbanding biosensor Au konvensional adalah 98% dan 202% masingmasing
    pada panjang gelombang 670 nm dan 785 nm. Ini menunjukkan bahawa cadangan biosensor SPR yang novel ini
    adalah lebih sensitif untuk pengesanan urea.
    MeSH terms: Methylglycosides; Molar; Urea; Biosensing Techniques; Mucin-1
  3. Roslinda Shamsudin, Syed Nuzul Fadzli Syed Adam, Siti Rohani Zainuddin, Banjuraizah Johar, Firuz Zainuddin
    Sains Malaysiana, 2018;47:1025-1031.
    The purpose of this study was to prepare macroporous glass ceramic scaffold by sol-gel glass synthesis and powder
    sintering method. Sodium nitrate was added during sol-gel process to obtain glass ceramic with mol composition of
    42.11% SiO2
    - 18.42% CaO - 29.82% Na2
    O - 9.65% P2
    O5
    . The glass particles were found to be thermally stable above
    900°C as indicated by TGA/DTA analysis. The dried glass particles obtained from sol-gel process were compacted and
    sintered at 1000°C for 3 h soaking time. Sintering crystallized the glass by 71.5% of crystallinity with tetracalcium catenahexaphosphate
    (V) (Ca4
    (P6
    O19) as the main crystalline phase as revealed by XRD analysis. Although glass crystallized
    during sintering, it showed a good in vitro bioactivity as apatite-like layer were deposited on the glass ceramic surface
    when immersed in simulated body fluid (SBF) for 14 days. SEM analysis proved the macroporous structure formation with
    pore size ranges between 30 and 350 µm due to foaming effect which occurred during sintering. Besides that, the glass
    ceramic surface formed into vitrified-like due to fluxing effect during sintering thus affected the porosity and densification
    measurement done by Archimedes test. In conclusion, the presence of sodium oxide in sol-gel glass ceramic composition
    by 29.82 mol % with sintering temperature at 1000°C is able to produce bioactive and macroporous glass ceramic that
    potentially be used as medical scaffold material.
  4. Shittu Abdullahi, Supian Samat, Muhamad Samudi Yasir, Aznan Fazli Ismail
    Sains Malaysiana, 2018;47:1017-1023.
    This research reports the annual effective dose of dwellers based on the finding of natural radioactivity concentrations in
    Malaysian tiles. A total of 30 tiles samples obtained from the manufacturer or bought directly from local hardware store.
    Natural radioactivity was analyzed using gamma spectrometry system for 12 h counting times. The activity concentration
    of 226Ra, 232Th, and 40K in the analyzed samples ranged from 37.50 – 158.05 Bq kg-1, 42.22 – 80.19 Bq kg-1 and 349.46 –
    750.18 Bq kg-1, respectively. The determined radium equivalent activity was below than the recommended limit of 370
    Bq kg-1. The external dose received by dwellers due to natural radionuclides in tiles were projected for 1, 5, 10, 20 and
    50 years through six exposure pathways using Resrad-build computer code. The results showed that the annual effective
    dose received by dwellers increased for the investigated timelines but still lower than the annual recommended limit of
    1500 µSv. The simulation result also indicates that radon gas was the primary radiation exposure which contributes
    80-94 % from the total radiation exposure to dwellers.
  5. Maria Abu Bakar, Azman Jalar, Roslina Ismail, Azman Jalar
    Sains Malaysiana, 2018;47:1011-1016.
    Sifat fizik dan mekanik sambungan pateri pada papan litar bercetak (PCB) sangat bergantung kepada bahan pateri
    dan permukaan penglogaman PCB. Kemajuan penyelidikan dan pembangunan bahan pateri bebas plumbum membuka
    peluang untuk menghasilkan sambungan pateri yang mempunyai kebolehtahanan yang tinggi. PCB/Cu merupakan PCB
    tanpa kemasan digunakan sebagai sampel kawalan manakala dua PCB yang lain iaitu PCB/ImSn (immersion tin) dan
    PCB/ENiG (electroless nickel immersion gold) dipilih untuk mengkaji kestabilan sambungan pateri. Sambungan pateri
    pada kemasan permukaan yang berbeza didedahkan kepada penyimpanan suhu tinggi (HTS) pada suhu 175°C selama
    1000 jam untuk mengkaji perubahan sifat mikromekanik. Ujian pelekukan nano memberikan sifat mikromekanik yang
    bersifat setempat. Perubahan kekerasan antarasambungan SAC 0307 selepas HTS ialah 66 MPa bagi PCB/Cu, 107
    MPa bagi PCB/ImSn dan 45 MPa bagi PCB/ENiG. Analisis terhadap sifat mikromekanik mendapati bahawa PCB/ENiG
    menunjukkan perubahan nilai yang minimum berbanding dengan PCB/Cu dan PCB/ImSn. Ini menunjukkan PCB/ENiG
    memberikan kestabilan sifat mikromekanik yang tinggi selepas didedahkan pada HTS pada suhu 175°C selama 1000 jam.
  6. Azman Jalar, Roslina Ismail, Maria Abu Bakar, Azman Jalar, Najib Saedi Ibrahim, Mohd Ariffin Ambak
    Sains Malaysiana, 2018;47:1005-1010.
    Pewarnaan pes pateri membuka suatu ruang kepada keperluan dalam teknologi untuk proses pengenalpastian, penandaan,
    piawaian, pengujian dan penilaian terhadap antarasambungan pes pateri. Dua jenis pigmen pewarna iaitu hijau (G)
    dan bercahaya dalam gelap (GD) digunakan untuk mengkaji kesan pewarnaan sambungan pateri ke atas kestabilan
    antarasambungan pateri Sn-3.0Ag-0.5Cu (SAC 305). Pes pateri tanpa warna digunakan sebagai sampel kawalan untuk
    membandingkan keputusan kajian. Uji kaji penuaan sesuhu digunakan untuk melihat perubahan pertumbuhan sebatian
    antara logam (IMC). Pigmen pewarna GD dengan peratusan sebanyak 5% telah menunjukkan kestabilan pertumbuhan
    IMC dengan perubahan pertumbuhan yang paling rendah iaitu sebanyak 5.6 µm bagi sambungan pateri yang berwarna
    berbanding dengan peratusan pigmen pewarna yang lebih tinggi dengan perubahan pertumbuhan IMC sehingga 9 µm
    selepas didedahkan kepada penuaan sesuhu pada 150°C selama 1000 jam. Walau bagaimanapun, kestabilan pertumbuhan
    IMC dengan penggunaan pes pateri berwarna adalah lebih rendah berbanding dengan pes pateri tidak berwarna.
    Maka penambahan pigmen pewarna hendaklah dipertimbangkan dengan mengambil kira kestabilan mikrostruktur dan
    pertumbuhan lapisan IMC supaya tidak menjejaskan kualiti dan kebolehharapan sesuatu sambungan pateri.
  7. Fazly Amri Mohd, Khairul Nizam Abdul Maulud, Othman A. Karim, Rawshan Ara Begum, Siti Norsakinah Selamat
    Sains Malaysiana, 2018;47:991-997.
    Malaysia has a long coastline stretching over 4,809 km where more than 1,300 km of beaches are experiencing erosion.
    Coastal erosion is recognised as the permanent loss of land and habitats along the shoreline resulting in the changes
    of the coast. Thus, it is important to detect and monitor shoreline changes especially in Pahang coast by identifying the
    rate of shoreline erosion and accretion. This study used temporal data and high spatial resolution imagery (SPOT 5) using
    remote sensing and GIS techniques to monitor shoreline changes along 10 study locations, which is from Cherating to
    Pekan of the Pahang coast. The total length of shoreline changes is about 14 km (14035.10 m) where all these areas are
    very likely to experience erosion ranging from 0.1 to 94.7 ha. On the other hand, these coastal areas found a minimal
    accretion with increased sediment from 0.1 to 2.8 ha. Overall, the coastal areas are exposed to higher erosion process
    than accretion with a very high vulnerability of erosion rate from 1.8 to 20.9 meter per year. The findings on monitoring
    shoreline changes and identifying vulnerable erosion areas might be useful in the policy and decision making for
    sustainable coastal management.
    MeSH terms: Conservation of Natural Resources; Decision Making; Malaysia; Ecosystem; Geographic Information Systems; Policy; Remote Sensing Technology
  8. Mohd Nizar K, Abd Jamil Z, Isharudin M, Hazandy A
    Sains Malaysiana, 2018;47:961-969.
    The presence of abundant oil palm residues in Malaysia prompted the need to utilize this waste to avoid environmental
    pollution. This waste was abundant at the oil palm mill and accounted for almost 50% of production. The study was
    conducted to determine the morphological effect of Palm Oil Mill Effluent (POME) sludge on the maize growth performance
    and gas exchange. Physicochemical, growth morphology and gas exchange was measured after treated with POME sludge
    from different treatment pond systems: Mixing, anaerobic, facultative, algae and dumping. The results indicated the
    pH, C, and CEC of mixing the < anaerobic < facultative < algae < dumping ponds. There was a significant presence of
    macronutrient (N, Mg, Ca, Fe, S) in the treated POME sludge, contrary to the presence of heavy metal (Cd, Cu, Ni and
    Pb) elements which were not significantly different in all the treatments and lower than WHO/FAO standard. Root Shoot
    Ratio (RSR) and Specific Leaf Area (SLA) indicated significant difference in biomass accumulation and yield compared to
    the control. The gas exchange variable was a significant difference on stomata conductivity (Gs) and transpiration rate
    (E). However, the POME sludge from the facultative, algae and dumping ponds showed positive correlations between net
    photosynthesis, stomata conductivity and transpiration rate. Indeed, the increased transpiration rate (E) was correlated
    with stomata conductance (Gs) after treatment with anaerobic, facultative, algae and dumping ponds. In conclusion, the
    POME sludge amendment was able to increase the maize biomass and yield.
    MeSH terms: Zea mays; Environmental Pollution; Lead; Malaysia; Photosynthesis; Sewage; World Health Organization; Plant Leaves; Plant Roots; Biomass; Metals, Heavy; Ponds
  9. Jesús Luengo Fereira, Heraclio Reyes Rivas, Luz Elena Carlos Medrano, Iovanna Toscano, Minerva Anaya Alvarez
    Sains Malaysiana, 2018;47:971-976.
    This study has been carried out to evaluate the clinical and radiographic CTZ (Chloramphenicol-Tetracycline-Zinc
    Eugenol Oxide) antibiotic paste in pulpotomies of primary molars. A Quasi-experimental study in 43 primary molars
    of children aged 3 to 7 years. Pulpotomies were performed on the selected patients with the CTZ antibiotic paste. Teeth
    were restored with glass ionomer and preformed steel metal crowns. Clinical and radiographic evaluation was performed
    at 6 and 12 months. SPSS V-19 program for data analysis and chi-square test was used up to 5%. Success rates were
    observed during the evaluation periods of time. 93% (x2
    = 0.446, p>0.05) and 88.4% (x2
    = 0.431, p>0.05) of the clinical form;
    97.7% (x2
    = 0.534, p>0.05) and 93% (x2
    = 0.553, p>0.05) were radiographic, at 6 and 12 months, respectively. The CTZ antibiotic
    paste is an alternative in the treatment of pulpotomy of molars. It provides an antimicrobial effect, decreased operative time, without
    causing trauma to the pediatric patient.
    MeSH terms: Acrylic Resins; Anti-Infective Agents; Anti-Bacterial Agents; Child; Chloramphenicol; Eugenol; Humans; Molar; Pulpotomy; Silicon Dioxide; Steel; Tetracycline; Zinc; Operative Time
  10. Hasmida Mohd-Nasir, Siti Hamidah Mohd-Setapar
    Sains Malaysiana, 2018;47:951-959.
    Consumer consciousness on the concept of natural-based ingredients triggers the natural cosmetics market to grow. The
    active compounds in natural ingredients offer valuable bioactivities such as antioxidant, photoprotection, anti-aging
    and anti-inflammatory actions that useful for skincare, hair care and dental care. This review presents an overview on
    natural ingredient, especially plant-derived, used in cosmetic products and the examples of Malaysian plants used for
    cosmetic purposes.
    MeSH terms: Anti-Inflammatory Agents; Antioxidants; Consciousness; Cosmetics; Dental Care; Hair; Skin Care
  11. Wan Elina Faradilla Wan Khalid, Lee YH, Mohamad Nasir Mat Arip
    Sains Malaysiana, 2018;47:941-949.
    Cellulose nanomaterial with rod-like structure and highly crystalline order, usually formed by elimination of the amorphous region from cellulose during acid hydrolysis. Cellulose nanomaterial with the property of biocompatibility and nontoxicity can be used for enzyme immobilization. In this work, urease enzyme was used as a model enzyme to study the surface modification of cellulose nanomaterial and its potential for biosensor application. The cellulose nanocrystal (CNC) surface was modified using 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-mediated oxidation to introduce the carboxyl group at C6 primary alcohol. The success of enzyme immobilization and surface modification was confirmed using chemical tests and measured using UV-Visible spectrophotometer. The immobilization strategy was then applied for biosensor application for urea detection. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques were used for electroanalytical characterization of the urea biosensor.
    MeSH terms: Cellulose; Cyclic N-Oxides; Enzymes, Immobilized; Hydrolysis; Urea; Urease; Biosensing Techniques; Nanoparticles
  12. Wun FML, Muhd Hafizi Zainal, Syahidah Mohd Tahir, Ishak B. Ahmad, Mohammad B. Kassim
    Sains Malaysiana, 2018;47:923-929.
    The presence of two different chromophores in benzothiazole molecule namely benzothiazole and aromatic rings lead to
    interesting chemical and biological properties that attract more researches on the compounds. Three new benzothiazolylbenzoythiourea
    compounds namely 1-(1,3-benzothiazol-2-yl)-3-(benzoylthiourea) (BBT), 1-(1,3-benzothiazol-2-yl)-3-
    (4-chlorobenzoylthiourea) (BBT-4Cl) and 1-(1,3-benzothiazol-2-yl)-3-(4-methoxybenzoylthiourea) (BBT-4OCH3
    ) with
    different electron withdrawing substituents (R) at the para positions on the benzene ring of benzoylthiourea ring have
    been synthesized from the reaction of R-benzoyl isothiocyanate (R= H, Cl, and OCH3
    ) and 2-aminobenzothiazole. The
    compounds were characterized by spectroscopic techniques (infrared, 1
    H proton NMR and UV-Vis). The IR spectra showed
    the frequency signals of n (C=O), n (C=S), n (N-H) at 1664-1673, 1238-1249 and 3031-3055 cm-1, respectively. The 1
    H
    proton NMR spectra showed the presence of N-H amine and amide signals in the region of (12.14-12.35) and (14.17-14.43)
    ppm, respectively. The proton signals of the two benzothiazole and benzoylthiourea moieties appear at 7.08-8.16 ppm.
    A theoretical study based on Density Functional Theory (DFT) and Time-Dependent (TD) DFT was conducted to optimize
    the geometrical structure and investigate the electronic properties of title compounds. The highest occupied molecular
    orbital (HOMO) was found on the benzothiazole moiety; while, the lowest-unoccupied molecular orbital (LUMO) was
    located at the benzoylthiourea fragment. The DFT optimized structures possessed an intramolecular hydrogen bonding
    and the types of para substituents used influenced the properties of hydrogen bonding.
    MeSH terms: Amides; Amines; Benzene; Electrons; Hydrogen Bonding; Models, Theoretical; Magnetic Resonance Spectroscopy; Protons; Isothiocyanates; Benzothiazoles
  13. Kamaruzaman S, Latifah M, Zainal Abidin M, Nusaibah S
    Sains Malaysiana, 2018;47:909-921.
    Phytophthora is one of the most important plant pathogens of perennial crops in the tropics. This study characterised
    the pathogen(s) responsible for cocoa black pod rot, rubber pod rot and durian stem canker. Eighteen Phytophthora
    isolates were collected from several states in Malaysia, namely Pahang, Johor and Selangor. A total of 12 Phytophthora
    palmivora and six Phytophthora nicotianae isolates were isolated and identified based on the morphological and
    molecular characteristics. Internal transcribed spacer (ITS) sequences enabled Phytophthora identification to species
    level. Inoculation of 18 isolates on detached leaves and unripen cocoa pods successfully demonstrated the progressive
    development of lesions on its original host. Lesions were also observed in all wounded detached leaves of young durian
    (clone D24) and rubber (clone RRIM600) and unripen cocoa pods (clone BAL244) regardless of host and isolates.
    Phytophthora isolates from durian (DSCI) and rubber (R4A) used to inoculate cocoa pods exhibited lesion sizes of 11.6±0.75
    and 9.6±0.64 mm, respectively. However, Phytophthora isolates from cocoa (CPR25) developed a longer length of lesion
    of 18.6±0.47 mm. On durian leaves, Phytophthora isolate from rubber (R4A) and cocoa (CPR25) recorded 11.73±1.04
    and 5.22±0.57 mm length of lesion while Phytophthora isolates from durian (DSCB4) produced 13.13±1.29 mm lesion on
    its native host. Isolates from cocoa (CPR22) and durian (DSCE3) infected rubber leaves with 3.74±0.48 and 2.55±0.31 mm
    length of lesion, in comparison to rubber isolates (R1B) with 5.43±0.23 mm length of lesion. Differences in the length
    of lesion demonstrated higher level of virulence on the native host.
  14. Nabila Elyana Adnan, Nur Atiqah Mohd Nasuha, Zanariah Abdullah, Yeun-mun Choo, Hairul Anuar Tajuddin
    Sains Malaysiana, 2018;47:903-906.
    Five di- and tri-substituted natural anthraquinones, i.e. nordamnacanthal (1), damnacanthal (2), rubiadin (3), 1-methoxy2-methyl-3-hydroxyanthraquinone
    (4) and 1-hydroxy-3-methoxyanthraquinone (5) were subjected to photophysical
    studies. The results indicated that steric hindrance and intramolecular hydrogen bonding are important factors that
    affect absorption and emission spectral of these natural anthraquinones. Besides that, emission properties were
    significantly enhanced with formation of intramolecular hydrogen bonding in 1,3-dihydroxy-2-aldehyde tri-substituted
    anthraquinone 1. This gave rise to formation of two additional quasi aromatic rings extending the π-conjugation system
    in the anthraquinone structure.
  15. Hee YY, Suhaimi Suratman, Norhayati Mohd Tahir, Timothy Jickells
    Sains Malaysiana, 2018;47:883-891.
    A seasonal study of phosphorus (P)-based nutrients was carried out in Sungai Setiu basin which is located in the southern
    region of the South China Sea (Malaysia) from July 2010 until June 2011. Parameters measured were dissolved inorganic
    P (DIP), dissolved organic P (DOP) and total particulate P (TPP). In addition, DOP concentration was size fractionated
    into high molecular weight (HMW, 0.7 µm-100 kDa), middle MW (MMW, 100-30 kDa) and low MW (LMW, <30 kDa). The
    results show that the mean concentration of P-based nutrients ranged between 3.2-7.0 µg/L P for DIP, 5.6-12.1 µg/L P
    for DOP and 9.2-119.4 µg/L P for TPP. Higher mean concentrations of P were recorded at urban and agricultural areas.
    In addition, the distribution of P was affected by season as higher mean concentrations of P were observed during the
    north-east monsoon due to the surface runoff of nutrients during this heavy raining season. The fractionation study of
    DOP further revealed that HMW fraction was abundant in Sungai Setiu, making up approximately 60% of the total DOP.
    This high percentage of HMW DOP was recorded at stations in the vicinity of agriculture area and towns suggesting
    an important contribution from anthropogenic activities. The LMW DOP fraction was not significantly associated with
    chlorophyll-a, suggesting that the phytoplankton might not be the predominant contributor for LMW fraction in this river.
    We suggest that these organic nutrient inputs should be monitored as part of the management of the aquatic system.
  16. Terence Ricky Chiu, Md Firoz Khan, Mohd Shahrul Mohd Nadzir, Haris Hafizal Abdul Hamid, Mohd Talib Latif, Mohd Shahrul Mohd Nadzir, et al.
    Sains Malaysiana, 2018;47:871-882.
    The individual compounds and sources of polycyclic aromatic hydrocarbon (PAHs) were studied in the surface sediments
    at 32 locations in the tourism area of Langkawi Island. A total of 15 PAHs were determined and quantified by gas
    chromatography coupled with mass spectrometry (GC-MS). The total PAH concentrations of surface sediments from
    Langkawi Island ranged from 228.13 to 990.25 ng/g and they were classified as being in the low to moderate pollution
    range. All sampling stations were dominated by high molecular weight PAHs with 4 rings (31.59%) and 5-6 rings (42.73%).
    The diagnostic ratio results showed that in most cases, the sampling stations have pyrogenic input. Further analysis
    using principal component analysis (PCA) combined with absolute principal component score (APCS) and multiple linear
    regression (MLR) showed that the natural gas emissions contributed to 57% of the total PAH concentration, 22% from the
    incomplete combustion and pyrolysis of fuel, 15% from pyrogenic and petrogenic sources and 6% from an undefined source.
    MeSH terms: Environmental Pollution; Gas Chromatography-Mass Spectrometry; Molecular Weight; Linear Models; Principal Component Analysis; Natural Gas; Islands
  17. Wan Juliana Wan Ahmad, Wan Norilani Wan Ismail, Latiff A, Muhammad Razali Salam
    Sains Malaysiana, 2018;47:861-869.
    Forest structure, diversity and above-ground biomass assessment are important to understand the structural and floristic
    dynamics of a mangrove forest ecosystem. Our study provides valuable comparative analysis between two areas of
    disturbed mangroves at Kisap Forest Reserve, Langkawi Island. The two study sites were swamp forest at C5 which was
    disrupted by harvesting activities for charcoal production and C7 was disturbed by lightning strikes. A total of 1,217
    and 390 trees measuring 1 cm diameter and above were enumerated in 0.25 ha plots at both sites. Seven mangrove plant
    species in C5 and eight in C7 were recorded. Ceriops tagal and Rhizophora apiculata were the most prominent species
    in the C5 and C7, respectively, whereby the Rhizophoraceae was the densest family at both sites. The major contributor
    of total basal area at C5 and C7 were C. tagal (5.02 m2
    /ha) and R. apiculata (11.14 m2
    /ha). Similarly, C. tagal (22.41 t/
    ha) and R. apiculata (111.75 t/ha) also contributed the highest biomass in C5 and C7, respectively. Diversity and species
    richness were higher at C7 H’=1.22; R’=1.17 compared to C5 H’= 0.76; R’=0.85 and low evenness at both sites. High
    similarity was indicated between the two sites by 93%. The distribution of individuals in C7 was homogenous than that
    of C5, which had more saplings. In conclusion, anthropogenic activities resulted in lower productivity of forest compared
    to natural disturbances.
  18. Cheku Nurul Aisyah, Ahmad Fudholi, Mohd Yusof Othman, Adnan Ibrahim, Mohd Hafidz Ruslan, Kamaruzzaman Sopian
    Sains Malaysiana, 2018;47:853-859.
    Kajian ini bertujuan untuk mereka bentuk dan mengkaji prestasi pengumpul fotovoltan-terma (PV/T) dengan menggunakan
    reka bentuk pengumpul terma aliran air secara pilin. Reka bentuk pengumpul terma aliran air secara pilin telah dibina
    semula daripada reka bentuk penyelidik sebelum ini. Pengumpul terma ini menggunakan saiz tiub yang lebih besar dan
    jarak antara tiub lebih dekat berbanding dengan reka bentuk penyelidik sebelum ini. Pengumpul PV/T ini telah diuji di
    bawah tiga keamatan yang berbeza iaitu 300, 500 dan 700 W/m2 serta diuji pada kadar aliran jisim air yang berbeza
    iaitu 0.01, 0.02 dan 0.04 kg/s. Pada keadaan yang sama, kecekapan fotovoltan, terma dan tergabung juga menunjukkan
    nilai yang paling tinggi, iaitu 4.18%, 76.68% dan 80.86%. Kecekapan terma yang dihasilkan pada kajian ini lebih tinggi
    dibandingkan dengan kajian sebelumnya.
    MeSH terms: Color; Pallor; Fimbriae Proteins; Tetrahydroisoquinolines
  19. Noor Intan Saffinaz Anuar, Sarani Zakaria, Hatika Kaco, Wang Chun hong, Chia CH, Husna Shazwani Abdullah
    Sains Malaysiana, 2018;47:839-851.
    The physico-mechanical and chemical properties of enzyme retting kenaf and shredded empty fruit bunch of oil palm
    fibres (EFB) were analyzed by chemical extraction, microscopic, spectroscopic, thermal and X-ray diffraction method.
    Polypropylene (PP), a petroleum based fibre, was also included to compare the properties of synthetic fibre with natural
    fibres. Chemical extraction analysis showed that cellulose was the major component in both kenaf and EFB fibres which
    are 54% and 41.34%, respectively. Silica content of EFB was 5.29% higher than kenaf that was 2.21%. The result of
    thermogravimetric analysis showed that kenaf has higher thermal decomposition rate compared to EFB fibre. However,
    the residue for EFB fibre was higher than kenaf due to higher content in inorganic materials. The residual content of PP
    fibre was only 1.13% which was lower than the natural fibre. The diameter of EFB fibre bundle was 341.7 µm that was
    three times higher than kenaf. Microscopy study demonstrated that EFB surface was rough, porous and embedded with
    silica while kenaf showed smooth surface with small pith. Higher porosity in EFB was due to the lower fibre density that
    was 1.5 kg/cm3 compared to kenaf that was 1.62 kg/cm3. Kenaf has illustrated significant higher tensile strength (426.4
    MPa) than EFB (150 MPa) and this result is in parallel to the pattern of the crystalline value for both fibres, 65% and
    50.58%, respectively.
  20. Azmi H, Che Haron C, Ghani J, Suhaily M
    Sains Malaysiana, 2018;47:829-838.
    Serabut kenaf merupakan salah satu serabut berasaskan tumbuhan di dalam kumpulan serabut asli yang semakin luas
    penggunaannya. Serabut kenaf dicampurkan dengan bahan plastik (epoksi) bagi menghasilkan suatu bahan baharu
    dengan sifat mekanikal yang baik dengan kos pembuatan yang rendah. Bahan kerja ini terbahagi kepada dua jenis iaitu
    serabut kenaf ekaarah dan serabut kenaf tenunan. Uji kaji ini akan menumpukan kepada pembandingan kesan faktor
    pelekangan Fd yang terhasil semasa proses pemesinan kisar ke atas bahan komposit tersebut dengan penentuan set
    parameter mesin yang paling optimum bagi mengurangkan kesan Fd. Uji kaji dijalankan berdasarkan analisis kaedah
    gerak balas permukaan (RSM) dengan pendekatan reka bentuk Box-Behnken bagi mendapatkan hasil faktor bersandar
    terhadap sambutan. Faktor yang terlibat adalah kelajuan pemotongan, kadar suapan dan kedalaman pemotongan. Proses
    pengisaran secara lelurus (lurah) dilakukan bagi melihat kesan Fd yang terhasil dengan menggunakan perkakasan mata
    alat jenis Keluli Berkelajuan Tinggi (HSS) tidak bersalut hujung rata berdiameter 10 mm. Imej daripada mikroskop
    menunjukkan bahan komposit serabut kenaf ekaarah menghasilkan faktor pelekangan yang tinggi berbanding kesan
    ke atas bahan komposit serabut kenaf bertenun. Bagi set parameter optimum pula, bahan kerja serabut kenaf ekaarah
    ialah kelajuan pemotongan, kadar suapan dan kedalaman pemotongan yang rendah. Manakala bagi bahan kerja serabut
    kenaf bertenun, set parameter optimum adalah kelajuan pemotongan yang rendah dengan kadar suapan dan kedalaman
    pemotongan yang tinggi.
    MeSH terms: Animals; Ataxia Telangiectasia; Color; Pallor; Reptiles; Hibiscus
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