Displaying publications 81 - 100 of 2561 in total

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  1. Izhar Hussain, Sher Aslam Khan, Abid Farid, Naushad Ali, Sardar Ali, Shah Masaud, et al.
    Sains Malaysiana, 2018;47:2637-2645.
    It is of great importance to know about the genetic diversity, conservation and classification for further utilization of
    tomato germplasm resources. Therefore, 40 tomato accessions were evaluated on the basic of agro-morphological traits
    for genetic diversity in 2014. The experiment was conducted at Agricultural Research Farm, University of Haripur and
    farmer field in Swabi, Khyber Pakhtunkhwa, Pakistan. Principal component analysis showed that five out of 27 principal
    components with an eigenvalue above 1.0 were considered for 74.10% of the total variance. The major contributing traits
    in variations were days to flowering (DFL), days to fruiting (DFR), fruit size (FS), fruit weight plant-1 (FW), yield plot-1 (YPP),
    yield hectare-1 (YPH), leaf length (LL), predominant fruit shape (PDFS), fruit length (FL), fruit width (FWidth), clusters
    plant-1 (CPP), fruits plant-1
    (FPP) and plant height (PH). The scattered plot of the PC’s revealed that the accessions were
    scattered in all the quarters, which is also a representative that high level of genetic variability was present. FW and FL
    were positively correlated with YPH. However, the remaining yield components indirectly contributed YPH. Cluster analysis
    divided 40 accessions into four main clusters (I, II, III and IV), each of which having 12, 11, 07 and 10 accessions. The
    accessions in clusters I and II were statistically similar and performed better in terms of yield and yield related traits.
    Grouping into different clusters was associated with their agro-morphological differences. These results could be serving
    as a useful resource for further characterization, preservation and breeding programs.
  2. Azhar Ahmad, Gobithaasan R
    Sains Malaysiana, 2018;47:2205-2211.
    A quadratic Bézier representation withholds a curve segment with free from loops, cusps and inflection points. Furthermore,
    this rational form provides extra freedom to generate visually pleasing curves due to the existence of weights. In this
    paper, we propose sufficient conditions for rational quadratic Bézier curves to possess monotonic increasing/decreasing
    curvatures by means of monotone curvature tests which are based on the derivative of curvature functions. We have
    derived a simple interval of the middle weight that assures the construction of a family of rational quadratic Bézier curves
    to be planar spirals, which is characterized by the turning angle, end curvatures and the chords of control polygon.
    The proposed formulation can be used by CAD systems for aesthetic product design, highway/railway design and robot
    trajectory design avoiding unwanted curvature oscillations.
  3. Suraiya Mostafiz, Alina Wagiran, Nur Syafiqoh Johan, Nur Saliha Abdllah Zulkifli, Ng JM
    Sains Malaysiana, 2018;47:2647-2655.
    The development of an efficient tissue culture protocol for somatic embryo would facilitate the genetic modification in
    breeding program. The present study describes the reproducible protocols for three wetland Malaysian rice cultivars
    (MR232, MR220 and MR220-CL2) and upland rice (Bario) via somatic embryogenesis. In the present study, four preheat treatments (35, 40, 45 and 50°C) were applied to mature seeds with different imbibition periods (3, 5 and 7 days)
    prior to culture on MS media with 3 mg/L 2,4-D. The results showed that the cultivars exhibited the highest callus
    induction percentage from 45°C pre-heated seeds and 3 days imbibition (100%, 96%, 100% and 95% for MR232, MR220,
    MR220-CL2 and Bario, respectively). Callus was induced early ranging from 3 to 12 days compared to without pre-heat
    treatment. The regeneration efficiency for MR220 and MR220-CL2 cultivars was significantly higher compared to the
    control treatment. However, both 45°C and 25°C (control) treatments produced higher plantlet regeneration for MR232
    and Bario. This study observed that pre-heat treated seeds prior to callus induction did promote callusing and hence
    regeneration. These findings can be used to establish a suitable protocol for the in vitro regeneration system for several
    genetic improvements in the numerous stress tolerances of Malaysian rice.
  4. Ahmad Firdaus Khalid, Yoke KY, Jun JT
    Sains Malaysiana, 2018;47:2705-2711.
    The use of honey as a therapeutic agent dates back at 8000 years and has markedly increased interest into its potential
    health benefits. The by-products of the flower nectar have a complex chemical composition which promotes benefits in
    underlying mechanism of human diseases. Malaysian Tualang Honey (MTH) is a multifloral jungle honey produced by
    the rock bee (Apis dorsata). This review consolidates the results of carious studies involving biochemical assays of tissue
    culture and animal trials of anti-cancer properties of MTH. Often studied in the context of breast cancer cell lines, MTH
    has promising data for possible mechanisms in anti-cancer activity. These include apoptosis via depolarization of the
    mitochondrial membrane, caspase-dependent apoptosis, reduction of angiogenesis and the promotion of cell cycle arrest
    without posing cytotoxic effect on normal cell lines. Despite positive outcomes in tissue cultures, the oral administration
    of MTH in breast cancer animal models showed slower tumour progression, reduction in tumour size and better grading
    of histological features. The alleviation of breast carcinogenesis via modulation of hematologic, estrogenic and apoptotic
    activities promotes MTH as a promising anticancer agent. With confidence in a conclusion that MTH is a useful treatment
    for cancer, further experimental and clinical studies should be conducted.
  5. Suzita Ramli, Yaya Rukayadi, Lau Kah Yan
    Sains Malaysiana, 2018;47:2301-2310.
    Spore-forming bacteria, Bacillus sp., frequently been associated with the contamination of rice and other starchy
    products. Spores are more resistant to antimicrobial treatments than its vegetative cells. The extract of Indonesian bay
    leaf (Syzygium polyanthum L.) was assessed for its antibacterial and sporicidal activities against vegetative cells and
    spores of B. cereus isolated from rice (25 strains). The results showed that S. polyanthum L. extract was able to inhibit
    the growth of vegetative cells of all B. cereus isolates with MICs ranged from 0.16 to 0.63 mg/mL and can kill with
    MBCs ranged from 0.31 to 2.50 mg/mL. The bactericidal endpoint for B. cereus BC-NP.8 in time kill curve was at 1.25
    mg/mL (8× MIC) after 4 h of incubation while for B. cereus ATCC 33019 was at 2.50 mg/mL (8× MIC). The sporicidal
    activity of S. polyanthum L. extract was not affected by different temperatures treatment and alteration of the pHs of
    extract. Therefore, this indicates that the extract was stable after exposed to pH3, 7 and 10 as well as temperature
    of 50, 80, and 121°C. Observation under on scanning electron microscope the structure of the B. cereus ATCC 33019
    spores was ruptured after being treated with 1% (w/v) S. polyanthum L. extract for 1 h. In conclusion, S. polyanthum L.
    extract had antibacterial and sporicidal activity against vegetative cells and spores of B. cereus isolated from rice.
  6. Mohamad Hanif Kamal Roslan, Che Aziz Ali, Kamal Roslan Mohamed
    Sains Malaysiana, 2018;47:2251-2258.
    Semakan semula litostratigrafi Formasi Singa dilakukan berdasarkan data-data baru yang diperoleh melalui kajian
    terbaru. Secara umumnya, Formasi Singa dominan dengan batu lumpur hitam yang berselang lapis dengan batu pasir
    nipis hingga sederhana tebal serta sedikit lapisan konglomerat. Kajian melibatkan analisis terhadap beberapa log
    sedimen yang telah direkodkan di lapangan. Kesemua log sedimen tersebut telah dikorelasikan untuk mendapatkan satu
    log komposit yang mewakili keseluruhan Formasi Singa. Berdasarkan kajian terperinci korelasi litologi yang dilakukan,
    cadangan litostratigrafi baru Formasi Singa mengandungi empat ahli iaitu Ahli Kentut, Ahli Ular, Ahli Selang dan Ahli
    Lembung. Ahli Kentut merupakan ahli yang paling tua diikuti dengan Ahli Ular, Ahli Selang dan Ahli Lembung. Ahli
    Ular di dalam Formasi Singa dianggap sebagai satu unit kekanta antara Ahli Kentut dengan Ahli Selang. Beberapa
    siri perubahan paras laut ditafsirkan sepanjang pengendapan batuan Formasi Singa dipercayai akibat daripada proses
    pencairan glasier yang menyebabkan paras laut meningkat dan pengendapan berterusan yang menyebabkan lembangan
    menjadi cetek dan paras laut menjadi rendah.
  7. Nurul Hidayah Yusof, Norrakiah Abdullah Sani, Farah Hannan Anuar, Mohd Suzeren Jamil, Saiful Irwan Zubairi
    Sains Malaysiana, 2018;47:2677-2683.
    Ultra-high temperature is a process that involves heating of milk to a very high temperature to produce sterile milk products.
    However, food poisoning due to consumption of UHT milk still happen in Malaysia. This study was done to develop a
    film that is made by poly(L-lactic acid) (PLLA) to detect the presence of microorganisms in UHT milk products. UHT milk
    that was used in this study was full cream milk. Contaminated milk that contained Bacillus cereus was made to conduct
    a model system on the relationship between colony forming unit of microorganisms and contact angle. Contaminated
    milk was also used as a control sample to study the difference of milk properties between fresh and contaminated milk.
    Physicochemical analysis (Brix, colour, pH and contact angle) and microbiological analysis (total plate count) were
    done to UHT milk sample as soon as the packaging of the milk was unsealed. Analysis was done with 30 min time interval
    until 4 h and 30 min since the unsealing of packaging. The results showed that presence of microorganisms in UHT milk
    was detected after the milk product was unsealed and exposed to environment for 3 h and 30 min. Contact angle resulted
    from the presence of microorganisms in UHT milk was 64.34 - 65.44° with its colony forming unit, 2.1 – 3.9 cfu/mL.
    Therefore, the potential usage of contact angle on PLLA thin film with respect to colony forming unit (cfu) in detecting
    the presence of microorganisms in UHT milk product was attained and well modelled.
  8. Sufia Zulfa Ahmad, Yusuf Dauda Jikantoro, Norazak Senu, Fudziah Ismail, Yusuf Dauda Jikantoro
    Sains Malaysiana, 2018;47:2223-2230.
    In this paper, we develop algebraic order conditions for two-point block hybrid method up to order five using the approach
    of B-series. Based on the order conditions, we derive fifth order two-point block explicit hybrid method for solving
    special second order ordinary differential equations (ODEs), where the existing explicit hybrid method of order five is
    used to be the method at the first point. The method is then trigonometrically fitted so that it can be suitable for solving
    highly oscillatory problems arising from special second order ODEs. The new trigonometrically-fitted block method is
    tested using a set of oscillatory problems over a very large interval. Numerical results clearly showed the superiority
    of the method in terms of accuracy and execution time compared to other existing methods in the scientific literature.
  9. Shuhib Mamat, Mohamad Faizzi, Mohd Sukor Su’ait, Norasikin Ahmad Ludin, Kamaruzzaman Sopian, Nurul Akmaliah Dzulkurnain, et al.
    Sains Malaysiana, 2018;47:2667-2676.
    Kajian terhadap elektrolit polimer berasaskan 49% poli(metil metakrilat) cangkukan getah asli (MG49) dengan
    natrium iodida (NaI) dalam aplikasi sel suria terpeka pewarna (DSSC) telah dijalankan. Kesan kepekatan garam
    ke atas sifat elektrokimia, morfologi, kimia dan kehabluran MG49-NaI telah dianalisis menggunakan spektroskopi
    impedan elektrokimia (EIS), mikroskopi imbasan elektron (SEM), spektroskopi inframerah transformasi Fourier (FTIR)
    dan pembelauan sinar-X (XRD). Morfologi keratan rentas menunjukkan struktur membran berliang mikro dan homogen.
    Nilai kekonduksian ion tertinggi pada suhu bilik bagi membran elektrolit polimer MG49-NaI pada penambahan 30 %
    bt. garam NaI adalah 8.86 × 10-5 S cm-1. Analisis inframerah menunjukkan interaksi antara atom oksigen dengan ion
    natrium berlaku pada kumpulan berfungsi eter (C–O–C) dan karbonil (C=O). Sifat kehabluran MG49-NaI polimer
    elektrolit didapati berkurang dengan peningkatan kepekatan garam. Analisis kronoamperometri memberikan nilai
    nombor pindahan ion (tion) sebanyak 0.92 membuktikan elektrolit polimer MG49-NaI (30 % bt.) adalah pengkonduksi
    jenis ion. Ujian prestasi DSSC keadaan pepejal bagi FTO/TiO2
    -N719/MG49-NaI (30 % bt.)/I2
    /Pt sampel telah memberikan
    keputusan kecekapan setinggi 0.26% dengan prestasi fotovoltaik, Jsc, Voc dan ff masing-masing adalah 1.30 mA cm-2, 0.56
    V dan 34.91. Membran dalam keadaan pepejal-kuasi atau separa pepejal memberikan nilai kecekapan 3.48 % dengan
    nilai Voc = 0.75 V, Jsc = 12.71 mA cm-2 dan FF = 37.70.
  10. Anuar Jamaludin, Roslinda Nazar, Ioan Pop
    Sains Malaysiana, 2018;47:2213-2221.
    In this study, the effects of suction and injection on the mixed convection flow of a nanofluid, over a moving permeable
    vertical plate were discussed. A similarity variable was used to transform the governing equations to the ordinary
    differential equations, which were then solved numerically using the bvp4c programme from MATLAB. Dual solutions
    (upper and lower branches) were found within a certain range of the mixed convection parameter in assisting and
    opposing flow regions. A stability analysis was implemented to confirm that the upper branch solution was stable, while
    the lower branch solution was unstable.
  11. Kook Shih Ying, Lee Yook Heng, Nurul Izzaty Hassan, Siti Aishah Hasbullah
    Sains Malaysiana, 2018;47:2657-2666.
    A copper ion sensor based on a new bis-thiourea compound N1
    ,N3
    -bis[[3,5-bis(trifluoromethyl)phenyl]carbamothioyl]
    isophthalamide (or TPC) as neutral carrier was investigated. The immobilization of the TPC into poly(n-butyl acrylate)
    (pBA) membrane via drop casting and the sensor was characterized by potentiometry. The sensor fabricated from TPC
    only showed a good Nernstian response towards copper ion with a sensitivity slope of 28.81±0.53mV/decade in the range
    of 1.0 × 10-6 - 1.0 × 10-4 M. The limit of detection of this sensor was found to be 6.11 × 10-7 M and with short sensor
    response time (60 - 80 s). This sensor also demonstrated reversibility and reproducibility with 3.69% and 1.84% (Relative
    Standard Deviation, RSD), respectively. Based on the separate solution method (SSM), the logarithm selectivity coefficients
    were better than -2.00 for monovalent, divalent and trivalent cations and this confirmed that the sensor exhibited good
    selectivity towards copper ion. The sensor could attain optimum function without the need in the inclusion of either
    lipophilic anions as a membrane additive nor plasticizer as a membrane softener. Thus, these are the main advantages.
    The addition of lipophilic anions into the pBA membrane could cause the sensitivity and selectivity of the copper ion
    sensor based on ionophore TPC to deteriorate.
  12. Muhammad Asmu’i Abdul Rahim, Siti Meriam Zahari, Sarifah Radiah Shariff
    Sains Malaysiana, 2018;47:2195-2204.
    The application of the Variance Targeting Estimator (VTE) is considered in GJR-GARCH(1,1) model, under three
    misspecification scenarios, which are, model misspecification, initial parameters misspecification and innovation
    distribution assumption misspecification. A simulation study has been performed to evaluate the performance of VTE
    compared to commonly used, which is the Quasi Maximum Likelihood Estimator (QMLE). The data has been simulated
    under GJR-GARCH(1,1) process with initial parameters ω = 0.1, α = 0.05, β = 0.85, γ = 0.1 and an innovation with a
    true normal distribution. Three misspecification innovation assumptions, which are normal distribution, Student-t
    distribution and the GED distribution have been used. Meanwhile, for the misspecified initial parameters, the first initial
    parameters have been setup as ω = 1, α = 0, β = 0 and γ = 0. Furthermore, the application of VTE as an estimator has
    also been evaluated under real data sets and three selected indices, which are the FTSE Bursa Malaysia Kuala Lumpur
    Index (FBMKLCI), the Singapore Straits Time Index (STI) and the Jakarta Composite Index (JCI). Based on the results, VTE
    has performed very well compared to QMLE under both simulation and the applications of real data sets, which can be
    considered as an alternative estimator when performing GARCH model, especially the GJR-GARCH.
  13. Kai Yin Chong, Chin Hua Chia, Sarani Zakaria, Thi Hao Pham, David Lucas
    Sains Malaysiana, 2018;47:2171-2178.
    Natural rubber (NR) latex gloves are widely used as a very important barrier for healthcare workers. However, they
    can still be perforated easily by sharp devices and instruments. The aim of this study was to investigate the effect of the
    addition of graphene oxide (GO) to low-ammonia NR latex on its puncture resistance, mechanical properties and thermal
    stability. GO was synthesized using modified Hummers’ reaction. The produced GO was mixed into the NR latex solution at
    various doses (0.01-1.0 wt. %), followed by a coagulant dipping process using ceramic plates to produce film samples.
    Puncture resistance was enhanced by 12% with 1.0 wt. % GO/NR. Also, the incorporation of GO improved the stress at
    300% and 500%, the modulus at 300% and 500% and the tear strength of low-ammonia NR latex films.
  14. Lim CK, Nurul Fadhilah Marzuki, Goh YK, You KG, Kah JG, Rafidah Ahmad, et al.
    Sains Malaysiana, 2018;47:3061-3068.
    Basal stem rot disease of oil palm caused by Ganoderma boninense is one of the most devastating diseases in oil palm
    plantation resulting in low yield, loss of palm stands and shorter replanting cycle. To-date, there is no effective treatment
    for Ganoderma infected palms. Control measures, either chemical or cultural approaches, show varying degrees of
    effectiveness. The application of biological control agents which is environmental-friendly could be an attractive solution
    to overcome the problem. Earlier, we had isolated a mycoparasite, Scytalidium parasiticum, from the basidiomata of
    Ganoderma boninense. In vitro assay and nursery experiment showed that this fungus could suppress Ganoderma infection
    and reduce disease severity. However, metabolites which might contribute to the antagonistic or mycoparasitic effect
    remain unknown. In the current study, optimization of fungal sample processing, extraction, and analytical procedures
    were conducted to obtain metabolites from the maize substrate colonized by mycoparasitic ascomycetous Scytalidium
    parasiticum. This technique capable of producing sexual spores in sac-like organs. Untargeted metabolomics profiling
    was carried out by using Liquid Chromatography Time of Flight Mass Spectrometry (LC-ToF-MS). We found that
    S. parasiticum in both liquid- and solid-state cultivation gave higher metabolite when extracted with 60% methanol with
    1% formic acid in combination with homogenisation methods such as ultrasonication and grinding. The findings from
    this study are useful for optimisation of metabolite extraction from other fungi-Ganoderma-plant interactions.
  15. Zuhaili Zakaria, Sarani Zakaria, Chin HC, Sharifah Nabihah Syed Jaafar, Umar Adli Amran, Sinyee Gan, et al.
    Sains Malaysiana, 2018;47:2573-2580.
    In this study oil palm empty fruit bunches (EFB) fibres was used to synthesize biophenolic resin (BPR) at a different
    formaldehyde/liquefied empty fruit bunches (F/LEFB) molar ratio which is 1.0, 1.5 and 2.0. The higher molar ratio of F/
    LEFB used has resulted in an increased of viscosity and solid content of BPR resin. The first decomposition of BPR resin
    occured around 86 to 130°C due to the evaporation of low molecular weight substance which were water, free phenol
    and formaldehyde. Glass fibre reinforced biophenolic composite (BPC) and glass fibre reinforced biophenolic elastomer
    composite (BPEC) was successfully fabricated using BPR resin. The impact strength and flexural strain of BPEC were
    higher than that of BPC. The impact strength of BPEC 1.5 was the highest at 47.71 kJm-2. However, the flexural strength
    of BPEC was lower compared with BPC, which the highest flexural strength was obtained by BPC 1.0 at 65.18 MPa. The
    cross-sectional image from scanning electron microscope (SEM) of BPEC and BPC confirmed the presence of epoxidized
    natural rubber (ENR) improved the compatibility between glass fibre and BPR resin.
  16. Muhammad aqil fitri rosli, kamalrul azlan azizan, goh hh
    Sains Malaysiana, 2018;47:3069-3075.
    Nepenthes, locally known as ‘periuk kera’ in Malaysia, is a fascinating species due to uniqueness in their morphology
    in having pitcher organ for carnivorous diet. The pitcher plant has been used for cooking traditional delicacies and
    as traditional remedies to treat illness. Hence, this species might possess beneficial health properties. This study
    aimed to compare the antioxidant activity of the pitcher extracts from Nepenthes ampullaria, Nepenthes rafflesiana
    and their hybrid, Nepenthes × hookeriana. The samples were extracted using methanol:chloroform:water (3:1:1)
    via sonication assisted extraction and the extracts were subjected to three different antioxidant assays, namely
    2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing power (FRAP) and total phenolic content (TPC). Extract from N.
    ampullaria exhibited the strongest radical scavenging activity (0.148 ± 0.04 mg/mL) with the highest ferric reducing
    power (0.009 ± 0.003 mg GA/mg dry weight) among the three species, whereas that of N. rafflesiana possessed the
    highest phenolic content (0.057 ± 0.017 mg GA/mg dry weight). However, the antioxidant capacities of the pitcher
    extracts were not significantly different (p>0.05) between the three species and were much lower than the gallic acid
    as a standard reference.
  17. Hussein Aliu Sule, Ahmad Ismail, Mohammad Noor Azmai Amal, Syaizwan Zahmir Zulkifli, Mohd Fauzul Aidil Mohd Roseli, Shamarina Shohaimi
    Sains Malaysiana, 2018;47:2589-2600.
    Tropical peat swamp forest (PSF) is one of the most endangered ecosystems in the world. However, the impacts of
    anthropogenic activities in PSF and its conversion area towards fish biodiversity are less understood. This study
    investigates the influences of water physico-chemical parameters on fish occurrences in peat swamp, paddy field and
    oil palm plantation in the North Selangor peat swamp forest (NSPSF), Selangor, Malaysia. Fish and water samples were
    collected from four sites located in the peat swamps, while two sites were located in the paddy field and oil palm plantation
    areas. Multivariate analyses were used to determine the associations between water qualities and fish occurrences in
    the three habitats. A total of 1,382 individual fish, belonging to 10 families, 15 genera and 20 species were collected.
    The family Cyprinidae had the highest representatives, followed by Bagridae and Osphronemidae. The most abundant
    species was Barbonymus schwanefeldii (Bleeker 1854), while the least abundant was Wallago leerii Bleeker, 1851. The
    paddy field and oil palm plantation area recorded significantly higher fish diversity and richness relative to peat swamp
    (p<0.05). The water physico-chemical parameters, such as pH, DO, NH3
    -N, PO4, SO4
    , and Cl2 showed no significant
    difference between paddy field and oil palm plantation (p>0.05), but was significantly different from the peat swamp
    (p<0.05). However, no water quality parameter was consistently observed to be associated with fish occurrences in all
    of the three habitats, but water temperature, NH3
    -N, Cl2, SO4
    , and EC were at least associated with fish occurrences in
    two habitats studied. This study confirmed that each habitat possess different water quality parameters associated with
    fish occurrences. Understanding all these ecological aspects could help future management and conservation of NSPSF.
  18. Mohd Azhar Hassan, Ahmad Hafiz Baharom, Muhammad Shafie Md Sah, Mohamad Zulkiffely A. Rahman, Mariatulqabtiah Abdul Razak
    Sains Malaysiana, 2018;47:3085-3094.
    There are various secondary metabolites that have been identified in Polygonum minus Huds. or kesum plant, but
    the production is often very low and depending on growth stage. Therefore, elicitation and in vitro techniques have
    been suggested as an effective way for inducing secondary metabolites production in plant. This study was conducted
    to determine the optimal conditions for P. minus root formation in vitro and to profile the metabolite content from
    P. minus root culture with and without elicitor treatment. From the root induction study, it was found that the fresh
    weight of induced root for nodal explant in MS liquid media supplemented with 0.5 mg/L NAA and shaken had the
    highest production (0.38±0.08 g) compared to other treatments including the control. The results from metabolite
    profile showed that the volatile compound of P. minus root produced without any elicitation contained 50.11% aliphatic
    (27.59% aldehide, 9.17% alkane and 13.35% others) and 19.39% sesquiterpene (β-caryophyllene, α-bergamotene,
    β-farnesene, α-caryophyllene dan β-curcumene) where the dodecanal compound (22.27%) and β-caryophyllene
    (8.09%) have the highest percentage value for aliphatic and sesquiterpene group, respectively. Moreover, elicitation of
    P. minus root culture using yeast extract at 100 mg/L concentration for 1 day demonstrated the ability to increase the
    production of secondary metabolites in many volatile compounds of kesum in vitro root including the sesquiterpene
    compounds compared to control treatment and other yeast extract elicitation treatments.
  19. Raba’atun Adawiyah Shamsuddin, Wan Ramli Wan Daud, Kim BH, Jamaliah Md. Jahim, Mimi Hani Abu Bakar, Wan Syaidatul Aqma Wan Mohd Noor
    Sains Malaysiana, 2018;47:3043-3049.
    Microbial fuel cells (MFCs) have a high potential application for simultaneous wastewater treatment and electricity
    generation. However, the choice of the electrode material and its design is critical and directly affect their performance.
    As an electrode of MFCs, the anode material with surface modifications is an attractive strategy to improve the power
    output. In this study, stainless steel (SS) and carbon steel (CS) was chosen as a metal anode, while graphite felt (GF)
    was used as a common anode. Heat treatment was performed to convert SS, CS and GF into efficient anodes for MFCs.
    The maximum current density and power density of the MFC-SS were achieved up till 762.14 mA/m2
    and 827.25 mW/m2
    ,
    respectively, which were higher than MFC-CS (641.95 mA/m2
    and 260.14 mW/m2
    ) and MFC-GF (728.30 mA/m2
    and 307.89
    mW/m2
    ). Electrochemical impedance spectroscopy of MFC-SS showed better catalytic activity compared to MFC-CS and
    MFC-GF anode, also supported by cyclic voltammetry test.
  20. Hemabarathy Bharatham, Siti Fathiah Masre, Leo Hwee Xien, Nurnadiah Ahmad
    Sains Malaysiana, 2018;47:2557-2563.
    In vivo stability of biomaterial-based bone scaffolds often present a significant drawback in the development of materials
    for tissue engineering purpose. Previously developed nanobiocomposite bone scaffold using alginate and nano cockle shell
    powder has shown ideal characteristics. However, it showed high degradation rate and reduced stability in an in vivo
    setting. In this study, we aim to observe the effect of cross-linking glutaraldehyde (GA) in three different concentrations
    of 0.5%, 1% and 2% during the fabrication process as a potential factor in increasing scaffold stability. Microstructure
    observations of scaffolds using scanning electron microscope (SEM) showed all scaffolds crossed linked with GA and
    control had an ideal pore size ranging from 166.8-203.5 µm. Increase in porosity compared to the control scaffolds
    was observed in scaffolds cross-linked with 2% GA which also presented better structural integrity as scored through
    semi-quantitative methods. Tested pH values during the degradation period showed that scaffolds from all groups
    remained within the range of 7.73-8.76. In vitro studies using osteoblast showed no significant changes in cell viability
    but a significant increase in ALP enzyme levels in scaffold cross-linked with 2% GA. The calcium content released from
    all scaffold showed significant differences within and between the groups. It can be concluded that the use of GA in the
    preparation stage of the scaffold did not affect the growth and proliferation of osteoblast and use of 2% GA showed
    improved scaffold structural integrity and porosity.
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