Displaying publications 21 - 40 of 65 in total

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  1. Safiah Sabrina Hassan, Intan Nabihah Ahmad Fadzil, Anida Yusoff, Khalilah Abdul Khalil
    Science Letters, 2020;14(1):49-58.
    MyJurnal
    Nowadays, probiotic bacteria are extensively used in beverages application to deliver beneficial health effect to the consumer upon ingestion. Different entrapment techniques can be used to maintain the viability of probiotic bacteria during processing as well as during storage of beverage products. Development of artificial microcapsules from entrapment techniques are to support the growth and to provide protection on probiotic cells from unfavorable external conditions that may affect the viability of probiotics in beverages. Techniques that usually applied for probiotic entrapment in beverages are microencapsulation, emulsification, spray drying and extrusion. Biomaterials such as alginate, carrageenan, whey protein, gelatin, chitosan and starch are the most commonly used matrix in entrapment of lactic acid bacteria. Entrapment of probiotic is applied on beverages products such as fruit juice, yoghurt and ice cream
  2. Amirul Hazim Kamarulzaman, Wan Maisarah Mukhtar
    Science Letters, 2020;14(1):14-20.
    MyJurnal
    A hybrid U-shaped-microbend fiber optic evanescent wave sensor was developed by combining two types
    of bending structures on the optical communication single mode optical fiber (SMF28). To study the
    effect optical microbending on the output power, corrugated plates consisted of cylindrical structured
    surface with various distance between the glass rods of 6 cm, 12 cm and 18 cm were constructed. The
    macrobending effect was introduced by bending the SMF into two shapes, namely U-shaped and Sshaped. The bare SMF with various bending designs were immersed into numerous water sources from
    Sg. Simin, Sg. Batang Benar and Sg. Klang. The output demonstrated that Sg. Simin was the most
    polluted river, followed by Sg. Klang and Sg. Batang Benar using U-shaped microbend SMF with
    distance between glass rod of 6cm and 1310 nm laser source. This result showed an excellent agreement
    with water quality index (WQI) data released by the Department of Environment (DOE), Malaysia.
    Maximum optical output power was obtained by using Sg. Simin’s water sample due to better light
    absorption from the evanescent waves by the pollutant particles, that avoided light leakage in comparison
    with less polluted water sources. The optimum sensing performance was successfully resulted by using
    U-shaped SMF due to its durability and uniform evanescent waves radiated from the cladding. In
    conclusion, the hybrid U-shaped-microbend SMF sensor based on evanescent waves propagation portrays
    an excellent potential to detect water pollution by monitoring the presence of pollutants around the fiber
  3. Nur Aimi Jani, Izzatul Syifa Azizan, Nur Fatin Razak, Mohd Muzamir Mahat, Weesiong Chiu, Saadah Abdul Rahman
    Science Letters, 2020;14(1):1-5.
    MyJurnal
    The influence of pH of the electrolyte used during anodization of Titanium substrate has been
    investigated in order to determine the optimum pH condition to form self-organized Titanium dioxide
    (TiO2) nanotubes (NTs) structure. The TiO2 NTs was formed by anodizing Titanium substrate in an
    electrolyte containing 1M of sodium sulfate (Na2SO4) with 0.7 g of ammonium fluoride (NH4F) for 180
    minutes with potential 20 V. The optimum conditions were determined by characterization using FESEM
    and XRD analysis. As shown in the result, it can be summarized that pH of the anodization electrolyte can
    affect the length and diameter of the NTs as confirmed by FESEM images. FESEM result shows that, the
    length of nanotubes increased as the pH increased which are from 50 nm to 424 nm for pH 5 and pH 7,
    respectively. However, at higher pH more than 7, the nanotube structure was collapsed and only form
    bulk oxide film. The FESEM result also supported by the XRD result as the peak at 24°
    increased up from
    pH 3 to pH 7 and drop at pH 9.
  4. Bazlee Abu Bakar, Wan Razarinah Wan Abdul Razak, Che Puteh Osman
    Science Letters, 2020;14(1):7-12.
    MyJurnal
    Food poisoning is one of the most common diseases in the world in which are caused by ingesting
    foodborne pathogens. Study was conducted to determine the antimicrobial activity of Murayya koenigii
    leaves extract on foodborne pathogens namely Salmonella typhi ATCC 14028, Staphylococcus aureus
    ATCC 25923, Bacillus cereus ATCC 11778, Escherichia coli ATCC 25922, Candida albicans ATCC
    10231 and Aspergillus niger ATCC 16404. The antimicrobial activity was determined at four different
    concentrations of 150 mg/mL, 200 mg/mL, 250 mg/mL and 300 mg/mL S. typhi was the most sensitive to
    M. koenigii extract at concentration 300 mg/mL with zone of inhibition diameter mean value of 8.67 ±
    0.67 mm followed by E. coli, S. aureus and B. cereus with zone of inhibition diameter mean values of
    8.33 ± 0.88 mm, 8.00 ± 0 mm and 7.67 ± 0.33 mm. C. albicans and A. niger were resistant to the extract.
    The minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs)
    against S. typhi, S. aureus, B. cereus and E. coli were 75 mg/mL, 150 mg/mL 125 mg/mL and 100 mg/mL
    respectively. There were no significant differences on the concentrations of M. koenigii extract on the
    zone of inhibition diameter produced (p=0.056). M. koenigii leaves extract exhibit antibacterial activity
    but no antifungal activity.
  5. Ruziman,Hasya,Hannani,, Pardi,Faezah,
    Science Letters, 2021;15(2):148-158.
    MyJurnal
    ABSTRACT
    Kuala Langat South Forest Reserve (KLSFR) was the main highlight when Selangor State
    Agriculture Corporation proposed to acquire the whole of KLSFR (about 6,908 ha) for the
    establishment of oil palm plantations. Many parties expressed their concern and opposed the plan
    as it would lead to the destruction of the forest and its biodiversity. As such, this study was aimed
    to determine the forest structure and tree species composition to conserve and sustainably manage
    the forest. Seven plots of 40 m x 20 m covering 0.56 ha were established randomly in KLSFR. All
    trees with 5 cm diameter breast height (DBH) and above were tagged, measured and identified.
    Voucher specimens were then taken for further verification purposes. The floristic composition of
    KLSFR consists of 335 individuals represented by 47 tree species from 21 families. Annonaceae,
    Guttiferaceae and Myristicaceae were the most speciose families with five species recorded for
    each family. Goniothalamus malayanus and Koompassia malaccensis were considered to have
    absolute dominance at the study site with Important Value index of 14.73 % and 14.19 %,
    respectively. KLSFR recorded low Shannon-Weiner Diversity index of H’ = 2.85 (H’max = 3.81)
    and Margalef’s Richness Index with DMG = 7.91. Evenness (E) index of 0.75 portrayed that the
    tree species are almost equally abundant in the study area. Total trees biomass was estimated at
    406.90 t/ha, represented by 349.61 t/ha of above ground biomass (AGB) and 57.29 t/ha of below
    ground biomass (BGB). The study indicated that KLSFR has uniform distribution of individuals
    with mixed species composition of trees. Tree distribution showed the pattern of De iocourt’s
    factor procedure (inverse J distribution) where number of tree decreases with the increase in
    diameter, representing the natural regeneration of the forest
  6. Ajmal,Jahid,, Harinder,Rai,Singh,
    Science Letters, 2021;15(2):2-9.
    MyJurnal
    ABSTRACT
    This study reports on the abundance and distribution of mangrove gastropods from Kuala Selangor
    Nature Park, Malaysia (KSNP). The line transect method with quadrats (5m x 5m) was employed
    to sample the gastropods. Gastropods were collected from the leaves, branches, stems and roots of
    trees and the mangrove floor. Nineteen gastropod taxa from seven families were recorded from the
    Bruguiera, mixed (Bruguiera, Avicennia and Rhizophora), Avicennia and Rhizophora zones.
    Avicennia sp. recorded the largest Girth at Breast Height (GBH) (mean±sd=37.3±18.2 cm) while
    Bruguiera sp. recorded the smallest GBH (mean=22.36±8 cm). The overall density of the gastropods at KSNP was 0.85 no/m2.The gastropod density was higher at the Avicennia & Rhizophora zone (150-200m (closer to the mudflats) (0.064±0.084 no/m2) followed by the mixed
    zone (50-150m) (0.046±0.30 no/m2) and lowest at the Bruguiera zone (0-50m) (0.08±0.080 no/m2) (closer to the coastal bund). Gastropod density between sampling zones did not vary significantly (p>0.05) but generally increased from the bund towards the mudflat edge. Further
    studies of the role of gastropods in the coastal food chain, as bio-indicators of habitat change and as potential food source for local populace are needed.
  7. Nurul,Elyni,Mat,Shaari,, Deny,Susanti,, Shafida,Abd,Hamid,
    Science Letters, 2021;15(2):14-22.
    MyJurnal
    ABSTRACT
    Calcium oxalate is one of the most common components in urolithiasis. Its treatment includes the
    use of synthetic drugs, ultrasound and surgery. However, cheaper alternative treatment using
    herbal medicine with less adverse side effect is preferred. Essential oils from Thai basil (Ocimum
    bacilicum L.), Vietnamese coriander (Persicaria odorata) and Chinese parsley (Coriandum
    sativum L.) were extracted and investigated for antiurolithic activity based on calcium oxalate
    crystallisation. Most of the crystals formed in control sample were hexagonal calcium oxalate
    monohydrate with sizes ranging between 3 to 4 m. The size of the crystals was found to be slightly
    reduced in O. bacilicum oil (2-4 m) at high concentration with less aggregation of crystals.
    Samples with P. odorata oil gave smaller crystal size (3 m) mainly in dehydrate form and the oil
    was also found to inhibit the aggregation of the crystals at high concentration. C. sativum oil
    enhanced crystallisation (5-6 m) with increased concentration and showed high aggregation of
    the crystals. This preliminary study shows the therapeutic potential of these medicinal plants to be
    used in traditional anti-urolithic therapy.
  8. Hazwani,Mohd,Yusof,, Sharaniza ,Ab-Rahim,, Wan,Zurinah,Wan,Ngah,, Sheila,Nathan,, A,Rahman,A,Jamal,, Musalmah,Mazlan,
    Science Letters, 2021;15(2):27-36.
    MyJurnal
    ABSTRACT
    Metabolic footprinting involves the determination of metabolites excreted or secreted by the cells.
    This study aimed to identify the differential extracellular metabolites in colorectal cancer (CRC)
    cells for the determination of molecular changes that occur as CRC progresses. CRC cells at
    different stages ie; SW 1116 (stage A), HT 29 and SW 480 (stage B), HCT 15 and DLD-1 (stage
    C), and HCT 116 (stage D) were grown in culture. The media in which the cells were grown are
    subjected to metabolomics profiling using Liquid Chromatography Mass SpectrometryQuadrupole Time of Flight (LC/MS Q-TOF). Statistical and metabolic pathway analysis was
    performed using Metaboanalyst software and identification of metabolites was determined by the
    METLIN database. A total of 27 differential extracellular metabolites were identified in CRC cells
    of different stages compared to stage A cells. Data from the Partial least squares-discriminant
    analysis (PLS-DA) score plot shows a clear separation between CRC cells of different stages with
    a few overlaps between stage B and C. Further analysis using variable importance in projection
    (VIP) revealed 14 differential extracellular metabolites that were most significant in differentiating
    CRC cells of the advanced stages from stage A which are 5-hydroxy-L-tryptophan,
    indoleacetaldehyde, 4,5-dimethylthiazole, 8-oxodiacetoxyscirpenol, bisnorbiotin, 5-amino-6-
    (5'phosphoribosylamino) uracil, glyceryl 5-hydroxydecanoate, sphinganine, 8,8-diethoxy-2,6-
    dimethyl-2-octanol, l-cystine, thiamine acetic acid, phytosphingosine, PE
    (20:4(5Z,8Z,11Z,14Z)/22:6(4Z,7Z,10Z,13Z,16Z,19Z)), N-(2R-hydroxypentacosano-yl)-2Samino-1,3S,4R-octadecanetriol. The different expressions of metabolites may indicate altered
    metabolic pathways in the more advanced CRC cells compared to stage A. This study highlights
    the importance of conducting both metabolomics profiling of extracellular and intracellular to
    generate a more complete understanding on the molecular changes that occur as CRC progresses
  9. Hajar,Ar,Rahmah,Nasri,, Mohamad,Shafiq,Mohd,Ibrahim,, Insyirah,Kamarulzaman,, Musliana,Mustaffa,
    Science Letters, 2021;15(2):43-53.
    MyJurnal
    ABSTRACT
    The obturation quality of GuttaFlow Bioseal in curved root canals is not commonly investigated although there has been a current approach toward utilizing this material in extracted molars in recent years. This study assessed the obturated surface area, extrusion of root filling material
    beyond the apical foramen and duration of obturation procedure in curved root canals using monocone obturation technique. Access cavity was prepared in 20 human mandibular molars. Root canals with curvature of more than 10 as determined according to Schneider’s method were
    included. Samples were prepared using Hyflex CM rotary files and divided into two groups (n=10): Group 1 [gutta-percha cone and GuttaFlow Bioseal] and Group 2 [gutta-percha cone and RoekoSeal Automix root canal sealer]. The duration of obturation procedure was recorded and obturation radiographs were taken. Samples were bisected and the mesial roots were sectioned horizontally to obtain 3 root segments; apical, middle and coronal. All resected roots were mounted on brass stubs, sputter-coated with thin platinum coating and observed under scanning electron microscope (SEM) at 70x magnification. The SEM images were transferred to the SketchAndCalc Area Calculator software. No statistically significant differences in the obturated surface area and extrusion of root filling material were observed between Group 1 and 2, irrespective of the status of root canal curvature. Duration for obturation in severe root canal curvatures between Group 1 and 2 were statistically significant. Obturated surface area and extrusion of root filling material were not affected by the root canal curvature, however duration for obturation using GuttaFlow Bioseal in severe root canal curvatures was slightly longer.
  10. Wan,Alif,Afiq,Wan,Nor,Ruddin,, Lailatul,Jalilah,Mohd,Ridah,, Nurul,Yaqin,Mohd,Nor,, Hamizah,Ismail,, Norafiza,Zainuddin,
    Science Letters, 2021;15(2):61-76.
    MyJurnal
    ABSTRACT
    The growing interest in biomedical studies has brought RNA from biofluids including plasma, as
    promising candidates for genetics profiling. The precision and reliability of an analysis in
    downstream application such as NanoString nCounter® MAX Analysis System (NanoString
    Technologies, Seattle, WA) ) depend on the RNA quality, purity and level. In this project,
    NanoString nCounter® miRNA panel was chosen due to rapid identification and ability to profile
    approximately 800 miRNAs per run which requires total RNAs from plasma with a minimum
    concentration of 33.3 ng/µL with 260/280 and 260/230 ratios of ≥1.8 for optimal results. Unlike
    tissues and cells, circulating RNAs in plasma are cell-free and are present in small sizes. However,
    the abundance of proteins and inhibitors in the plasma as possible contaminants could diminish
    the effectiveness of molecular isolation techniques and pose challenges in RNA isolation and
    quantification. This could skew data collection and elucidation. Therefore, the main objective is
    to determine the optimized plasma RNA isolation protocol to overcome problems in RNA quality
    and purity with regards NanoString nCounter® MAX Analysis System requirement. Several
    optimization steps were performed, including the addition of one chloroform extraction step with
    extra washing steps instead of conducting only once following the actual protocol. After
    conducting these steps, the average 260/280 ratio falls between 1.7 to 1.8, slightly increased
    compared to the results before optimization which was around 1.4 to 1.6 since these steps of
    optimization help to remove excess impurities including phenol and salt. Furthermore, increasing
    the incubation time in certain steps, for instance, after sample homogenization with Qiazol, during
    95% ethanol precipitation and after RNase-free water addition have boosted the RNA recovery
    allowing RNA concentration of 15 ng/µL and above to be obtained. Hence, the optimized plasma
    RNA isolation protocol was determined since several issues related to plasma RNA concentration
    and purity were significantly improved by performing the additional steps in the protocol.
  11. Norsuhaila,Rosmimi,Rosli,, Tengku,Shahrul,Anuar,, Mohd,Ilham,Adenan,, Roziah,Mohd,Janor,, Rohana,Ahmad,, Lay,Kek,Teh,, et al.
    Science Letters, 2021;15(2):91-99.
    MyJurnal
    ABSTRACT
    Academic achievement may be influenced by catechol-O-methyltransferase (COMT)
    polymorphism. A common functional polymorphism of COMT, the rs4680 is consistently being
    involved in the modulation of dopaminergic pathway and prefrontal cortex function which may
    predominantly affect cognitive functions. A total of 197 female participants were recruited in this
    study. The score of student’s grade point average (GPA) from the latest previous semester was
    used as the measurement of academic achievement. The COMT polymorphism was genotyped
    using tetra primer allele specific polymerase chain reaction. The findings indicated that there
    were 8 (4.1 %), 72 (36.5 %), and 117 (59.4 %) participants harbouring Met/Met, Met/Val, and
    Val/Val genotype for COMT polymorphism respectively. All the genotype distributions of
    COMT polymorphism were consistent with Hardy-Weinberg equilibrium (χ2 = 0.495, p > 0.05).
    The one-way analysis of variance (ANOVA) result demonstrated that participants bearing
    Met/Met genotype had a better achievement in GPA as compared to the other COMT genotypes
    (p = 0.001). These findings support evidence that the affective role of COMT polymorphism
    might overwhelm cognitive abilities in measures of academic achievement like GPA.
  12. Syed,Lukhman,, Nadiah,Natar,, Nureel,Ghani,, Amira,Shukor,, Syazana,Nazeri,, Syahirul,Ikhwan,, et al.
    Science Letters, 2021;15(2):103-111.
    MyJurnal
    ABSTRACT
    Polyaniline (PANI) and Kronos C doped Titanium dioxide (TiO2) was fabricated as PANI/TiO2
    solar cell and reported on its simple photovoltaic performance detected by using voltameter and
    tested for stability for 12 months. The PANI and TiO2 were coated onto different indium tin oxide
    (ITO) glass plates by using a drop-casting method and sandwich attached for simple solar cell
    preparation. PT4 sample was the optimum solar cell with 0.2: 0.2 g of PANI: TiO2 ratio under 2
    cm2 surface area based on the highest voltage produces from 100 mW cm-1
    of light intensity metal
    highlight lamp. No voltage was detected for PT7 where the single layer TiO2 coated without PANI
    attached for solar cell system using same fabrication. It shows that PANI has a significant role in
    functionalizing the photovoltaic system. The C-N stretching of aromatic amine and C-N stretching
    for the benzenoid at peaks of 1222 and 1166 cm-1
    respectively in FTIR spectra has confirmed the
    PANI structure supported by an XRD pattern. TP4 has the highest photovoltaic performance
    compared to other types of TiO2 based on the electron lifetime (τe) and the voltage produced was
    sustained up to 12 months.
  13. Sharir,Aizat,Kamaruddin,, Nor,Atikah,Husna,Ahmad,Nasir,, Nur,Syafiqah,Rahim,, Norlin,Shuhaime,, Mohd,Akmal,Hashim,, Ahmad,Suhail,Khazali,, et al.
    Science Letters, 2021;15(2):117-132.
    MyJurnal
    ABSTRACT
    This research is conducted to assess the accuracy of spline interpolation methods to predict and
    model the surface water pH of Pulau Tuba, Langkawi, Kedah, Malaysia. In-situ sampling
    activities using pH-meter and Geographic Positioning Systems (GPS) were carried out during
    high tides and at noon in November 2018. The development of spatial models was constructed
    using Regularized and Tension spline methods. Then, validation of models was carried out to
    compare the observed and predicted values of pH using correlation analysis, regression analysis,
    and error analysis. The accuracy of the developed map was calculated using the overall accuracy
    equation. This research found that the regularized spline method had more accuracy in estimating
    surface water pH variability than the tension spline method. Pearson correlation coefficient (r),
    Coefficient of determination (R2
    ), Mean Absolute Error (MAE) and Root Mean Square Error
    (RMSE) were reported at 0.896, 0.803, 0.0265 and 0.0344 for the regularized spline method,
    respectively. The developed spatial model was then transformed into a map by adding map
    elements such as legend, title, north arrow, and scales for effective visualization. The developed
    map has an accuracy of 87.50%. The surface water pH was found at the range of 7-8. Low
    reading of pH is expected due to the addition of rainwater to the coastal water of Pulau Tuba,
    Langkawi, Kedah. The research outcomes would benefit government and non-government
    agencies to monitor the coastal and ocean acidification and the development of strategic policies
    and rules to reduce the impact of anthropogenic activities and climate changes for this area.
  14. Liyana,Musa,, Sabrilhakim,Sidek,, Firdaus,Yusof @ Alias,, Azlan,Azha,Musa,, Mohammad,Hanafiah,, Mazuin,Mohd,Razall,
    Science Letters, 2021;15(2):136-145.
    MyJurnal
    ABSTRACT
    Glaucoma is a disease that is chronic in nature and indistinctive at an early stage, leading to late
    detection. It has become a major public health problem and a leading cause of irreversible
    blindness worldwide. The proton magnetic resonance spectroscopy (1H-MRS), of late, has been
    utilised to evaluate metabolites concentration in the brain, especially for detecting
    neurodegenerative disease. Considering that glaucoma is a neurodegenerative disease, studies on
    the concentration of metabolites using 1H-MRS in glaucoma patients could be investigated. This
    scoping review aims to examine the extent, range, and nature of studies on the 1H-MRS technique
    in glaucoma disease. The literature search was conducted using MEDLINE, CINAHL and
    SCOPUS, dated from 2000 until 2019. Studies on glaucoma using 1H-MRS were considered. Any
    processing method used to characterise the metabolite concentration generated by the 1H-MRS
    protocol has also been considered. Nine full-text studies were yielded after hundreds of literature
    identification, screening, and eligibility assessment. The included studies sought to determine the
    feasibility, change, and comparability of metabolite concentrations in glaucoma patients using 1HMRS with more studies utilising single-voxel spectroscopy (SVS) technique. The chosen anatomy
    of interest could have been influenced by several criteria, including the association between
    anatomy and the research query and the volume-sizing capabilities of the 1H-MRS technique. Six
    (6) metabolites were significantly identified, and quantified, including N-acetyl aspartate,
    Creatine, Choline, Myo-Inositol, Lactate and Glutamate-Glutamine. This scoping review points
    out the 1H-MRS application in different types and severity of glaucoma, highlighting the
    information on the type of patients, the detected metabolites in the anatomy involved, the 1H-MRS
    technique used and the raw data decipherment processing software. Future studies are needed to
    validate existing glaucoma studies and to explore the potential of detecting incipient glaucoma.
  15. Mohamad Zainurin MN, Harman N, Jasnie F, Lo CW
    Science Letters, 2021;15(2):80-87.
    MyJurnal DOI: 10.24191/sl.v15i2.13829
    Etlingera coccinea, a native Borneon Zingiberaceae are found to exert allelopathic effect on some weed species. The objective of this study is to investigate the allelopathic effects of hexane (80%), methanol (80%), ethyl acetate (80%) extracts from the dried powder of both stem and leaf of E. coccinea on mung bean (Vigna radiata) and Siam weed (Chromolaena odorata). The phytochemical screening of both stem and leaf crude extracts elicited saponin, tannin, flavonoid, and terpenoid, which are targeted bioactive compounds for allelopathy. The allelopathic activity was assessed by evaluating their effects on seed germination and percentage of radicle and shoot growth. The results showed that both stem and leaf extracts have a suppressive effect on the mung bean development during in-vitro bioassay. The methanolic extracts of both stem and leaf showed the most significant suppression (100%) than other solvent extracts. In the pot experiment, the methanolic stem extracts suppressed the Siam weed’s germination by 57 ± 0.13% and the methanolic leaf extracts suppressed the growth by 46 ± 0.29%. The present study shows that E. coccinea methanolic extract has the potential as bio-herbicide.
  16. Mariyah Faizal, Normah Ismail
    Science Letters, 2016;10(1):4-7.
    MyJurnal
    This study was carried out to extract, partially
    purify and characterise protease from guava peel. The
    extracted protease was purified using 60% ammonium sulfate
    precipitation method followed by gel filtration
    chromatography. The obtained proteases were analysed for
    protein concentration, proteolytic activity, total proteolytic
    activity, specific activity, percent recovery, purification fold,
    molecular weight distribution, optimum temperature and pH.
    Guava peel contains 7.10% protein. The optimum temperature and pH of the protease was achieved within the range of 40 to
    60°C and pH 4 to 6, respectively, where maximum activity
    identified was 50°C and pH 5. Total activity decreased with the
    purification steps involving 60% ammonium sulfate
    precipitation and dialysis but subsequently increased after
    being subjected to gel filtration chromatography. This study
    suggested that further purification using gel filtration
    chromatography increases the proteolytic activity of guava peel
    protease.
  17. Mohd Noor Zairi Mohd Sapri, Azizah Hanom Ahmad
    Science Letters, 2016;10(1):11-13.
    MyJurnal
    Solid polymer electrolytes electrolytes based Poly
    (ethylene oxide) (PEO) complexed with sodium
    trifluoromethanesulfonate (NaCF3SO3
    ) salt were prepared by
    using solution cast technique. Ion-polymer ionic conductivity
    and interaction studies have been reported by Electrical
    Impedance spectroscopy (EIS) and Fourier transform infrared
    spectroscopy (FTIR). FTIR studies suggested that there are
    stronger interaction between Na+
    ions and the polymer than
    interaction of anions cations of the salt. The temperature
    dependance electrical conductivity of polymer electrolytes films
    follow Arrhenius relation and the low activation energy 0.2993
    eV was observed for PEO-18 wt. % NaCF3SO3 below 323 K.
  18. Mohd Tajudin Mohd Ali, Nurhana Faujan
    Science Letters, 2016;10(1):14-17.
    MyJurnal
    Glycosylation of betulinic acid with
    -D-glucose-pentaacetate was successfully synthesized in the
    presence of boron trifluoro etherate (BF3
    .Et2O) in pyridine to
    give betulinic acid bisglucoside in 92.8% yield. Further
    treatment of bisglucosides with methanol and sodium metal
    produced high polarity betulinic acid glucoside with 45%
    yield. Evaluation of human myeloid leukemia cell (HL60) and
    human T4-lymphoblastoid cell (CEMSS) activities with both
    synthesized compounds revealed that both compounds were
    less potent compared to betulinic acid itself but their water
    solubility were slightly increase.
  19. Ahmad Lutfi Anis, Talari, Mahesh Kumar, Widyani Darham
    Science Letters, 2016;10(1):24-26.
    MyJurnal
    Superhydrophobic surfaces have attracted significant research interest because of their use for design of water-repellent and self-cleaning coatings. A superhydrophobic surface can be created by modifying a rough surface with a material of low surface energy through a sol-gel coating technique. Adjusting the amount of precursor and the low surface energy material can optimize the hydrophobicity of the coating. In this work, different ratios (4:1, 3:2, 1:1 and 2:3) of silane: alumina coatings were synthesized and applied on glass substrates through sol-gel method. Characterization of the coated samples showed that volume ratios of silane sol and alumina sol in sol-gel coating affected the superhydrophobicity of the coated glass substrate. The solution of alumina sol and silane sol with ratio 4:1 produced superhydrophobic films with contact angle for water larger than 150 and FESEM images showed very intense roughness compared to the other ratios.
  20. Masar Hadi Jawad, Azizan Aziz, Sulaiman Ab Ghani
    Science Letters, 2016;11(2):1-10.
    MyJurnal
    A differential pulse adsorptive cathodic stripping voltammetric (DPAdCSV) method for the determination of lead levels in water sample by using pairs of ligands (complexing agents) / – nitrite and 1,10 phennanthroline - nitrite were investigated. Variables affecting the response such as pH, supporting electrolyte, deposition potential, deposition time, stirring speed, drop size, sweep rate, pulse amplitude and ligand concentration were studied. Under optimized conditions the relationship between peak current and lead concentration with 2,2ʹ-bipyridine - nitrite and 1,10 phennanthroline - nitrite were linear in the range of 10 - 500 ng mL-1 and 7–500 ng mL-1 with limit of detection of 0.48 ng mL-1 and 0.36 ng mL -1 respectively . The relative standard deviations (RSD) for 9 determinations of 25 ng mL−1 Pb (II) using 2,2ʹ-bipyridine - nitrite and 1,10 phennanthroline - nitrite were 1.74% and 1.84%, respectively. The values obtained for the proposed technique correlated well with those of atomic absorption spectrometry (AAS) as the standard method with correlation coefficient (R2 ) of 0.9991 and 0.9986. The method was applied for the determination of lead in sea, lake and tap waters. The interferences of other metals and major salts present were negligible except iron (III) and Aluminum (III)
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