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Fulltext Authenticity Testing and Detection of Eurycoma longifolia in Commercial Herbal Products Using Bar-High Resolution Melting Analysis

Fadzil NF, Wagiran A, Mohd Salleh F, Abdullah S, Mohd Izham NH

Genes (Basel), 2018 Aug 12;9(8).
PMID: 30103564 DOI: 10.3390/genes9080408

The present study demonstrated High Resolution Melting (HRM) analysis combined with DNA barcode (Bar-HRM) as a fast and highly sensitive technique for detecting adulterants in Eurycoma longifolia commercial herbal products. Targeting the DNA barcoding of the chloroplastic region-ribulose biphosphate carboxylase large chain (rbcL) and the nuclear ribosomal region- internal transcribed spacer 2 (ITS2), PCR amplification and HRM analysis using saturated Eva green dye as the source of fluorescence signals, was accomplished by employing a real-time cycler. The results were further validated by sequencing to identify unknown sequence from Genbank database and to generate phylogenetic tree using neighbour joint (NJ) analysis. Both of the DNA markers exhibited a distinguishable melting temperature and shape of the normalised curve between the reference and the adulterants. In the case of species identification, ITS2 was more successful in differentiating between species. Additionally, detection of admixture sample containing small traces of targeted E. longifolia DNA (w/v) can be detected as low as 5% for rbcL and less than 1% for ITS2, proving the sensitivity and versatility of the HRM analysis. In conclusion, the Bar-HRM analysis is a fast and reliable technique that can effectively detect adulterants in herbal products. Therefore, this will be beneficial for regulatory agencies in order to regulate food safety issues.

Matched MeSH terms: Temperature
Fulltext Effect of Ratio in Ammonium Nitrate on the Structural, Microstructural, Magnetic, and AC Conductivity Properties of BaFe12O19

Azis RS, Che Muda NN, Hassan J, Shaari AH, Ibrahim IR, Mustaffa MS, et al.

Materials (Basel), 2018 Nov 06;11(11).
PMID: 30404131 DOI: 10.3390/ma11112190

This paper investigates the effect of the ratio of ammonium nitrate (AN) on the structural, microstructural, magnetic, and alternating current (AC) conductivity properties of barium hexaferrite (BaFe12O19). The BaFe12O19 were prepared by using the salt melt method. The samples were synthesized using different powder-to-salt weight ratio variations (1:3, 1:4, 1:5, 1:6 and 1:7) of BaCO₃ + Fe₂O₃ and ammonium nitrate salt. The NH₄NO₃ was melted on a hot plate at 170 °C. A mixture of BaCO₃ and Fe₂O₃ were added into the NH₄NO₃ melt solution and stirred for several hours using a magnetic stirrer under a controlled temperature of 170 °C. The heating temperature was then increased up to 260 °C for 24 hr to produce an ash powder. The x-ray diffraction (XRD) results show the intense peak of BaFe12O19 for all the samples and the presence of a small amount of the impurity Fe₂O₃ in the samples, at a ratio of 1:5 and 1:6. From the Fourier transform infra-red (FTIR) spectra, the band appears at 542.71 cm - 1 and 432.48 cm - 1 , which corresponding to metal⁻oxygen bending and the vibration of the octahedral sites of BaFe12O19. The field emission scanning electron microscope (FESEM) images show that the grains of the samples appear to stick each other and agglomerate at different masses throughout the image with the grain size 5.26, 5.88, 6.14, 6.22, and 6.18 µm for the ratios 1:3, 1:4, 1:5, 1:6, and 1:7 respectively. From the vibrating sample magnetometer (VSM) analysis, the magnetic properties of the sample ratio at 1:3 show the highest value of coercivity Hc of 1317 Oe, a saturation magnetization Ms of 91 emu/g, and a remnant Mr of 44 emu/g, respectively. As the temperature rises, the AC conductivity is increases with an increase in frequency.

Matched MeSH terms: Temperature
Fulltext Coughing Shih Tzu dog due to myxomatous mitral valve disease stage C2

Khor, K.H., Jessie-Bay, J.X.

Jurnal Veterinar Malaysia, 2018;30(1):15-19.
MyJurnal

Myxomatous Mitral Valve Disease is a degenerative condition of the mitral valves leaflets. A 10-year-old
male castrated Shih Tzu was presented with primary complaint of coughing. Clinical examination revealed normal
heart rate, respiratory rate and rectal temperature. Systolic murmur Grade IV/VI was heard at the left heart apex.
Thoracic radiographic findings were cardiomegaly with the vertebral heart score of 11.0 and had evidence of
cardiogenic pulmonary edema. Echocardiographic examination revealed thickening mitral valves with evidence of
moderate regurgitation observed. Based on the findings obtained, the dog was diagnosed with Myxomatous Mitral
Valve disease stage C2. Dog was treated with benazepril (0.5mg/kg), pimobendan (0.2mg/kg) with a combination of
furosemide (2mg/kg). Frusemide was gradually removed from the treatment regime as coughing improved over time.
The dog was no longer lethargy and even gained weight.

Matched MeSH terms: Temperature
Fulltext Knowledge and Concerns of Parents Regarding Childhood Fever at a Public Health Clinic in Kuching, East Malaysia

Bong WT, Tan CE

Open Access Maced J Med Sci, 2018 Oct 25;6(10):1928-1933.
PMID: 30455776 DOI: 10.3889/oamjms.2018.339

BACKGROUND: Parental anxiety regarding fever may be unwarranted as most cases are owing to self-limiting causes.
AIM: To assess the level of knowledge and concerns regarding childhood fever among parents with young children in a public health clinic in Kuching, East Malaysia.
METHODS: This cross-sectional study was conducted among parents recruited from a maternal and child health clinic, with children aged 6 months to 6 years. The participants completed a self-administered questionnaire regarding their knowledge and concerns about childhood fever. Descriptive statistical analyses were performed, and associations between dependent and independent variables were determined.
RESULTS: Only 26.1% of participants were found to have good knowledge. Knowledge regarding childhood fever was significantly associated with parent's ethnicity, education level, and household income. About 72% of parents were always worried about their child's illness. Three major reasons for their concerns were persistently rising temperature; discomfort caused by the fever, and feared complications of fever.
CONCLUSION: Excessive parental anxiety due to poor knowledge and misconceptions about fever may lead to poor quality of life and inappropriate management of fever. Healthcare providers may help by educating parents about fever and serious signs that indicate the need to seek healthcare advice.

Matched MeSH terms: Temperature
Fulltext Preparation and characterization of yttrium barium copper oxide (YBCO) superconductor with addition of cobalt oxide (Co3O4)

Jannah, A.N., Erwana, N.Y., Jamion, N.A.

Journal of Academia Universiti Teknologi MARA Negeri Sembilan, 2018;6(1):31-38.
MyJurnal

This study was carried out to investigate the electrical properties of YBCO sample as superconductor
and the effect of addition of Co3O4 on the superconducting properties of YBCO superconductor. The
YBCO sample was prepared by solid state reaction route. The samples were prepared by each with
weight percentage of cobalt oxide of x= 0.00, x= 0.01, x= 0.02 and x= 0.03. Electrical Conduction by
Multimeter, Fourier Transform Infrared (FTIR), Critical temperature (Tc) measurement, X-ray
Diffraction (XRD), and Scanning Electron Microscopy (SEM) were conducted for analysis.
Multimeter showed all samples were in electric conduction, FTIR showed that carbonyl compound in
the sample was removed after calcinations. Tc measurement showed that the critical temperature of
sample of x= 0.02 was increased compared to sample of x= 0.00. XRD showed all samples have
orthorhombic structure and SEM showed that the grain size was increased as increased the cobalt
addition in YBCO superconductor. Besides, the EDX also showed the composition of elements
YBCO were tally with chemicals used for pure YBCO and addition cobalt oxide into YBCO
superconductor.

Matched MeSH terms: Temperature
Fulltext Introduction to Photonics: Principles and the Most Recent Applications of Microstructures

Amiri IS, Azzuhri SRB, Jalil MA, Hairi HM, Ali J, Bunruangses M, et al.

Micromachines (Basel), 2018 Sep 11;9(9).
PMID: 30424385 DOI: 10.3390/mi9090452

Light has found applications in data transmission, such as optical fibers and waveguides and in optoelectronics. It consists of a series of electromagnetic waves, with particle behavior. Photonics involves the proper use of light as a tool for the benefit of humans. It is derived from the root word "photon", which connotes the tiniest entity of light analogous to an electron in electricity. Photonics have a broad range of scientific and technological applications that are practically limitless and include medical diagnostics, organic synthesis, communications, as well as fusion energy. This will enhance the quality of life in many areas such as communications and information technology, advanced manufacturing, defense, health, medicine, and energy. The signal transmission methods used in wireless photonic systems are digital baseband and RoF (Radio-over-Fiber) optical communication. Microwave photonics is considered to be one of the emerging research fields. The mid infrared (mid-IR) spectroscopy offers a principal means for biological structure analysis as well as nonintrusive measurements. There is a lower loss in the propagations involving waveguides. Waveguides have simple structures and are cost-efficient in comparison with optical fibers. These are important components due to their compactness, low profile, and many advantages over conventional metallic waveguides. Among the waveguides, optofluidic waveguides have been found to provide a very powerful foundation for building optofluidic sensors. These can be used to fabricate the biosensors based on fluorescence. In an optical fiber, the evanescent field excitation is employed to sense the environmental refractive index changes. Optical fibers as waveguides can be used as sensors to measure strain, temperature, pressure, displacements, vibrations, and other quantities by modifying a fiber. For some application areas, however, fiber-optic sensors are increasingly recognized as a technology with very interesting possibilities. In this review, we present the most common and recent applications of the optical fiber-based sensors. These kinds of sensors can be fabricated by a modification of the waveguide structures to enhance the evanescent field; therefore, direct interactions of the measurand with electromagnetic waves can be performed. In this research, the most recent applications of photonics components are studied and discussed.

Matched MeSH terms: Temperature
Parametric study of immobilized cellulase-polymethacrylate particle for the hydrolysis of carboxymethyl cellulose

Chan YW, Acquah C, Obeng EM, Dullah EC, Jeevanandam J, Ongkudon CM

Biochimie, 2019 Feb;157:204-212.
PMID: 30513369 DOI: 10.1016/j.biochi.2018.11.019

Biocarriers are pivotal in enhancing the reusability of biocatalyst that would otherwise be less economical for industrial application. Ever since the induction of enzymatic technology, varied materials have been assessed for their biocompatibility with enzymes of distinct functionalities. Herein, cellulase was immobilized onto polymethacrylate particles (ICP) as the biocarrier grafted with ethylenediamine (EDA) and glutaraldehyde (GA). Carboxymethyl cellulose (CMC) was used as a model substrate for activity assay. Enzyme immobilization loading was determined by quantifying the dry weight differential of ICP (pre-& post-immobilization). Cellulase was successfully demonstrated to be anchored upon ICP and validated by FTIR spectra analysis. The optimal condition for cellulase immobilization was determined to be pH 6 at 20 °C. The maximum CMCase activity was achieved at pH 5 and 50 °C. Residual activity of ∼50% was retained after three iterations and dipped to ∼18% on following cycle. Also, ICP displayed superior pH adaptability as compared to free cellulase. The specific activity of ICP was 65.14 ± 1.11% relative to similar amount of free cellulase.

Matched MeSH terms: Hot Temperature
Flocculation of Chlorella vulgaris by shell waste-derived bioflocculants for biodiesel production: Process optimization, characterization and kinetic studies

Suparmaniam U, Lam MK, Uemura Y, Shuit SH, Lim JW, Show PL, et al.

Sci Total Environ, 2020 Feb 01;702:134995.
PMID: 31710849 DOI: 10.1016/j.scitotenv.2019.134995

Flocculants are foreign particles that aggregate suspended microalgae cells and due to cost factor and toxicity, harvesting of microalgae biomass has shifted towards the use of bioflocculants. In this study, mild acid-extracted bioflocculants from waste chicken's eggshell and clam shell were used to harvest Chlorella vulgaris that was cultivated using chicken compost as nutrient source. It was found that a maximum of 99% flocculation efficiency can be attained at pH medium of 9.8 using 60 mg/L of hydrochloric acid-extracted chicken's eggshell bioflocculant at 50 °C of reaction temperature. On the other hand, 80 mg/L of hydrochloric acid-extracted clam shell bioflocculant was sufficient to recover C. vulgaris biomass at pH 9.8 and optimum temperature of 40 °C. The bioflocculants and bioflocs were characterized using microscopic, zeta potential, XRD, AAS and FT-IR analysis. The result revealed that calcium ions in the bioflocculants are the main contributor towards the flocculation of C. vulgaris, employing charge neutralization and sweeping as possible flocculation mechanisms. The kinetic parameters were best fitted pseudo-second order which resulted in R2 of 0.99 under optimal flocculation temperature. The results herein, disclosed the applicability of shell waste-derived bioflocculants for up-scaled microalgae harvesting for biodiesel production.

Matched MeSH terms: Temperature
Novel protocol optimized for microalgae lutein used as food additives

Low KL, Idris A, Mohd Yusof N

Food Chem, 2020 Mar 01;307:125631.
PMID: 31634761 DOI: 10.1016/j.foodchem.2019.125631

Lutein available in the current market is derived from marigold petals. However, extensive studies showed that microalgae are rich in lutein content and potentially exploitable for its dietary and other industrial applications. In this study, microwave assisted binary phase solvent extraction method (MABS) was the novel protocol being developed and optimized to achieve maximum lutein recovery from microalgae Scenedesmus sp. biomass. Results showed that 60% potassium hydroxide solution with acetone in the ratio of 0.1 (ml/ml) was the ideal binary phase solvent composition. Empirical model developed using response surface methodology revealed highest lutein content can be recovered through MABS extraction method at 55 °C treatment temperature, 36 min in extraction time, 0.7 (mg/ml) for biomass to solvent ratio, 250 Watt microwave power and 250 rpm stirring speed. This optimized novel protocol had increased the amount of lutein recovered by 130% and shorten the overall extraction time by 3-folds.

Matched MeSH terms: Hot Temperature
Fulltext Effects of Hybridized Organically Modified Montmorillonite and Cellulose Nanocrystals on Rheological Properties and Thermal Stability of K-Carrageenan Bio-Nanocomposite

Zakuwan SZ, Ahmad I

Nanomaterials (Basel), 2019 Oct 31;9(11).
PMID: 31683602 DOI: 10.3390/nano9111547

Herein, hybrid k-carrageenan bio-nanocomposite films were fabricated by using two types of nanofillers, organically modified montmorillonite (OMMT), and cellulose nanocrystals (CNCs). Hybrid bio-nanocomposite films were made by casting techniques employing 4 wt% of CNCs, OMMT, and hybridized CNCs/OMMT in a 1:1 ratio. The rheological and morphological properties and thermal stability of all composites were investigated using rotational rheometry, thermogravimetry analysis, differential scanning calorimetry, field emission scanning electron microscopy, and transmission electron microscopy (TEM). The results showed that the hybrid CNC/OMMT bio-nanocomposite exhibited significantly improved properties as compared to those for the bio-nanocomposites with single fillers due to the nanosize and homogenous nanofiller dispersion in the matrix. Rheological analysis of the hybrid bio-nanocomposite showed higher dynamic shear storage modulus and complex viscosity values when compared to those for the bio-nanocomposite with individual fillers. The TEM analysis of the hybridized CNC/OMMT bio-nanocomposite revealed that more particles were packed together in the CNC network, which restricted the matrix mobility. The heat resistance and thermal stability bio-nanocomposite k-carrageenan film enhanced rapidly with the addition of hybridized CNCs/OMMT to 275 °C. The hybridized CNCs/OMMT exhibited synergistic effects due to the good affinity through interfacial interactions, resulting in the improvement of the material properties.

Matched MeSH terms: Hot Temperature
Fulltext Cell surface proteins of cryptococcus neoformans mediate adherence and internalisation into mammalian cells

Choo, K.K., Chin, V.K., Chong, P.P., Ho, S.H., Yong, V.C.

JUMMEC, 2019;22(2):24-30.
MyJurnal

Cryptococcus neoformans is an encapsulated fungal pathogen that causes severe disease primarily in
immunocompromised patients. Adherence and internalisation of microbial pathogens into host cells often
begin with engagement of microbes to the surface receptors of host. However, the mechanisms involved
remain poorly understood. In this study, we investigated the association of cell surface determinants of C.
neoformans with mammalian cells. Our results showed that treatment with trypsin, but not paraformaldehyde
or heat killing, could reduce host-cryptococci interaction, suggesting the involvement of cell surface proteins
(CSPs) of C. neoformans in the interaction. We extended our investigations to determine the roles of CSPs
during cryptococci-host cells interaction by extracting and conjugating CSPs of C. neoformans to latex beads.
Conjugation of CSPs with both encapsulated and acapsular C. neoformans increased the association of latex
beads with mammalian alveolar epithelial cells, alveolar macrophages and monocyte-derived macrophages.
Further examination on the actin organisation of the host cells implied the involvement of actin-dependent
phagocytosis in the internalisation of C. neoformans in CSP-conjugated latex beads. We hypothesised that
CSPs present on the cell wall of C. neoformans mediate the adherence and actin-dependent phagocytosis
of cryptococci by mammalian cells. Our results warrant further studies on the exact role of CSPs in the
pathogenesis of cryptococcosis.

Matched MeSH terms: Hot Temperature
Tigecycline resistance may be associated with dysregulated response to stress in Mycobacterium abscessus

Ng HF, Ngeow YF, Yap SF, Zin T, Tan JL

Int J Med Microbiol, 2019 Nov 18.
PMID: 31784213 DOI: 10.1016/j.ijmm.2019.151380

Previously, we characterized 7C, a laboratory-derived tigecycline-resistant mutant of Mycobacterium abscessus ATCC 19977, and found that the resistance was conferred by a mutation in MAB_3542c, which encodes an RshA-like protein. In M. tuberculosis, RshA is an anti-sigma factor that negatively regulates the SigH-dependent heat/oxidative stress response. We hypothesized that this mutation in 7C might dysregulate the stress response which has been generally linked to antibiotic resistance. In this study, we tested this hypothesis by subjecting 7C to transcriptomic dissection using RNA sequencing. We found an over-expression of genes encoding the SigH ortholog, chaperones and oxidoreductases. In line with these findings, 7C demonstrated better survival against heat shock when compared to the wild-type ATCC 19977. Another interesting observation from the RNA-Seq analysis was the down-regulation of ribosomal protein-encoding genes. This highlights the possibility of ribosomal conformation changes which could negatively affect the binding of tigecycline to its target, leading to phenotypic resistance. We also demonstrated that transient resistance to tigecycline could be induced in the ATCC 19977 by elevated temperature. Taken together, these findings suggest that dysregulated stress response may be associated with tigecycline resistance in M. abscessus.

Matched MeSH terms: Temperature
Fulltext Release of bisphenol a from polycarbonate and polyethylene terephthalate drinking water bottles under different storage conditions and its associated health risk

Wen Min Yun, Yu Bin Ho, Eugenie Sin Sing Tan, Vivien How

Malaysian Journal of Medicine and Health Sciences, 2018;14(102):1-9.
MyJurnal

Bisphenol A (BPA) is a controversial plastics ingredient used mainly in the production of polycarbonate plastics (PC) and epoxy resins that widely used nowadays in food and drink packaging. Even though BPA is not involved in polyethylene terephthalate (PET) manufacturing, recent study had reported the present of BPA in PET water bottle. This study was conducted to investigate effects storage conditions on release of BPA from PC and PET bottled water as well as to assess health risks associated with consumption. Methods: Solid phase extraction (SPE) was used to extract the samples, followed by analysis using ultra high performance liquid chromatography with fluorescence detector (UHPLC-FLD). The possibility of developing chronic non-carcinogenic health risk among consumers of bottled water was evaluated using hazard quotient (HQ). Results: Results showed that BPA migrated from PC and PET water bottles at concentrations ranging from 9.13 to 257.67 ng/L and 11.53 ng/L to 269.87 ng/L respectively. Concentrations of BPA were higher in PET bottled water compared to PC bottled water across all storage conditions. Higher storage temperature and longer storage duration increased BPA concentrations in PC and PET bottled water. Concentrations of BPA in bottled water which were kept in a car and were exposed to sunlight were higher than control samples which were stored indoor at room temperature. Conclusion: No significant chronic non-carcinogenic health risks were calculated for daily ingestion of BPA-contaminated bottled water; calculated HQ was less than one.

Matched MeSH terms: Temperature
Fulltext Comparison of hydro-distillation, hydro-distillation with enzyme-assisted and supercritical fluid for the extraction of essential oil from pineapple peels

Mohamad N, Ramli N, Abd-Aziz S, Ibrahim MF

3 Biotech, 2019 Jun;9(6):234.
PMID: 31139549 DOI: 10.1007/s13205-019-1767-8

Pineapple peel is a potential feedstock for the extraction of essential oil due to the presence of aromatic compounds. To extract the essential oil from pineapple peels, three different methods were applied, i.e., (1) hydro-distillation (HD); (2) hydro-distillation with enzyme-assisted (HDEA); and (3) supercritical fluid extraction (SFE). SFE had successfully produced an essential oil with the yield of 0.17% (w/w) together with 0.64% (w/w) of concrete, whereby the HD and HDEA had only produced hydrosols with the yield of 70.65% (w/w) and 80.65% (w/w), respectively. Parameters' optimization for HD (substrate to solvent ratio, temperature, and extraction duration) and HDEA (cellulase loading and incubation duration) significantly affected the hydrosol yield, but did not extract out the essential oil. This is because only SFE had successfully ruptured the oil gland after observed under the scanning electron microscope. The essential oil obtained from SFE composed of mainly propanoic acid ethyl ester (40.25%), lactic acid ethyl ester (19.35%), 2-heptanol (15.02%), propanol (8.18%), 3-hexanone (2.60%), and butanoic acid ethyl ester (1.58%). In overall, it can be concluded that the SFE had successfully extracted the essential oil as compared to the HD and HDEA methods.

Matched MeSH terms: Temperature
Seasonal and spatial variability of selected surface water quality parameters in Setiu Wetland, Terengganu, Malaysia

Suratman S, Hussein A, Mohd Tahir N, Latif M, Mostapa R, Weston K

Sains Malaysiana, 2016;45:551-558.

This paper presents the results for surface water quality parameters measured in the Setiu Wetland, on the east coast of Malaysia, which feeds into the southern part of the South China Sea. There are no previous studies dealing with the seasonal and spatial variation of water quality in this area, despite numerous anthropogenic inputs into this ecologically and economically important wetland. The parameters measured were salinity, temperature, dissolved oxygen (DO), pH, biological oxygen demand (BOD) and total suspended solids (TSS). These parameters were sampled monthly from October 2009 to September 2010, during both the wet and dry seasons, at ten sampling stations distributed throughout the area. The physical water quality parameters were measured in situ whilst TSS and BOD were determined using the standard methods. A deterioration of water quality in the Setiu Wetland was observed in areas near agriculture and aquaculture activities. This was expected to be as a result of the use of fertilisers, waste from fish farm food and the waste products of aquaculture. The parameters measured showed lower mean values of surface salinity, temperature, DO, pH and TSS during the wet season relative to the dry season. In contrast, the concentration of BOD was high during the wet season and lowest in the dry season. Results obtained from this study clearly showed the surface physical water quality for the Setiu Wetland was highly influenced by anthropogenic activities and seasonal variation. Therefore, both factors must be considered to move towards proper management of this wetland.

Matched MeSH terms: Temperature
Effects of Yttria Doping on Some Properties of YBa2Cu3O7-Î´ Superconductor

Mustaffa Hj. Abdullah, Tan TK

Sains Malaysiana, 1997;26.

Samples of Y-Ba-Cu-O superconductor with nominal compositions of YBa2Cu3O7-d + x (weight %) Y2O3 (x = 0 - 15) were prepared by solid state reaction method using the Y2Cu2O5 and BaCuO2 precursors as the starting reagents. The X-ray diffraction (XRD) diffractograms for the doped samples (x> 0) show an additional non-superconducting Y2BaCuO5 (211) phase. The scanning electron microscope (SEM) micrographs show that the smaller Y2BaCuO5 grains are precipitated on the surface of the larger YBa2Cu3O7-d (YBCO) crystals. The grain size of the YBCO decreases with increasing yttria. The superconducting zero resistivity critical temperature (Tco) of the doped samples is very close to the Tco of the YBCO for x < 5, but it seems to be significantly decreasing for larger x. The transport critical current density (J) for x < 5 is enhanced due to magnetic flux pinning process by the 211 phase. However, Jc decreased for larger x due to the increase of weak links at the grain boundaries of the YBCO phase.
Sampel superkonduktor Y-Ba-Cu-O dengan komposisi nominal YBa2Cu3O7-d + x (% berat) Y2O3 (x = 0 -15) disediakan dengan kaedah tindakbalas keadaan pepejal menggunakan bahan pelopor Y2Cu2O5 dan BaCuO2 Difraktogram pembelauan sinar-X (XRD) bagi sampel yang didop (x > 0) menunjukkan wujudnya fasa tak mensuperkonduksi Y2BaCuO5 (211). Mikrograf mikroskop imbasan elektron (SEM) menunjukkan bahawa butiran Y2BaCuO5 yang lebih kecil itu termendap di atas permukaan hablur YBa2Cu3O7-d yang lebih besar. Saiz hablur YBCO mengecil dengan peningkatan yittria. Suhu genting kerintangan sifar (Tc) bagi sampel yang didop adalah hampir dengan Tco bagi YBCO untuk x<5, tetapi menurun dengan agak cepat untuk x yang lebih besar. Ketumpatan arus genting angkutan (J) untuk x < 5 meningkat jika dibandingkan dengan YBCO disebabkan oleh proses kepinan fluks magnet oleh fasa 211. Walau bagaimanapun, Jc menurun untuk x yang lebih tinggi kerana meningkatnya hubungan lemah pada sempadan butiran fasa YBCO.

Matched MeSH terms: Temperature
Investigation of the gelation mechanism between amino acid surfactant based microemulsion and Kappa-Carrageenan gel network

Nasima Akter, Shahidan Radiman, Faizal Mohamed, Nazaruddin Ramly, Putra EGR, Rini AS

Sains Malaysiana, 2014;43:203-209.

Kappa-carrageenan is one form of necessary hydrocolloid. Hydrocolloids are macromolecular materials, which swell upon absorption of water; in some cases, forming a stiff gel in the presence of additives. This property is very important to suspend nanocarriers into gel network, which provide them long time stability at a varying temperature range. In this work, we prepared microemulsion and trapped these particles inside the kappa-carrageenan gel network. The microemulsion was composed of sodium N-lauroylsarcosinate hydrate (SNLS), oleic acid and deionized water. The purpose of this study was to immobilize them into the gel network, giving longer shelf life at a range of temperatures for oral drug delivery. Morphological properties were investigated by transmission electron microscope (TEM), dynamic light scattering (DLS) and Fourier transform infrared (FTIR) spectra. The TEM results showed that microemulsions are trapped in the gel network, and the diameter of the microemulsions are below 100 nm, which is comparable with the DLS results. The important functional groups of kappa-carrageenan and microemulsion were shown from the FTIR result of the complex microemulsion gel. These results confirmed the interaction between SNLS based microemulsion and kappa- carrageenan gel.

Matched MeSH terms: Temperature
Liquefied residue of Kenaf core wood produced at different Phenol-Kenaf ratio

Saiful Bahari Bakarudin, Sarani Zakaria, Ching HC, Mohd Jani S

Sains Malaysiana, 2012;41:225-231.

Liquefactions of kenaf core wood were carried out at different phenol-kenaf (P/k) ratios. Characterizations of kenaf core wood liquefied residue were carried out to measure the degree of liquefaction. This provides a new approach to understand some fundamental aspects of the liquefaction reaction. Functional groups on the raw kenaf core wood and liquefied residue were examined using Fourier transform infrared spectroscopy (FTIR). The crystallinity index of the kenaf wood liquefied residue, which represents crystallinity changes of the cellulose component after the liquefaction process, was studied using X-ray diffraction (XRD). The surface morphology of the wood residue was observed using scanning electron microscopy (SEM). The thermal behavior of the residues was analyzed using thermogravimetric analysis (TGA). Abroad peak around 3450-3400 cm-1 representing OH stretching in lignin start to disappear as P/K ratio increases. The results showed that the higher the P/K ratio the greater the liquefaction of the lignin component in the kenaf core wood. The crystallinity index (CrI) on the kenaf liquefied residues increased with the increase in P/K ratio. SEM images showed that the small fragments attached on the liquefied kenaf residue surface were gradually removed as the P/K ratio was increased from 1.5/1.0 to 2.5/1.0, which is mainly attributed to the greater chemical penetration toward reactive site of the kenaf fibres. Residue content decreased as the P/K ratio increased from 1.5/1.0 to 2.5/1.0. TGA results showed the increase of heat resistance in the residue as the P/K ratio was increased.

Matched MeSH terms: Hot Temperature
Deposition and characterization of SnSe and CuInSe2 thin films by thermal evaporation technique from synthesized SnSe and CuInSe2 sources

Nordin Sabli, Zainal Abidin Talib, Chang CB, Wan Mahmood Mat Yunus, Zulkarnain Zainal, Hikmat S. Hilal, et al.

Sains Malaysiana, 2014;43:1061-1067.

Tin selenide (SnSe) and copper indium diselenide (CuInSe2) compounds were synthesized by high temperature reaction method using combination of sealed ampoule (at relatively low pressure ~10-1 Pa without inert gas) and heating at specific temperature profile in rocking furnace. Powder X-Ray diffraction analysis showed that the products involved only single phases of SnSe and of CuInSe2 only. Using the reaction products as source materials, the SnSe and CuInSe2 thin films were vacuum-deposited on glass substrates at room temperature. Structural, elemental, surface morphological and optical properties of the as-deposited films were studied by X-Ray diffraction (XRD), energy dispersive X-Ray (EDX) analysis, field emission scanning electron microscopy (FESEM) and UV-Vis-NIR spectroscopy. Single phase of SnSe and CuInSe2 films were obtained by thermal evaporation technique from synthesized SnSe and CuInSe2 compound without further treatment.

Matched MeSH terms: Temperature
Supervised and unsupervised artificial neural networks for analysis of diatom abundance in Tropical Putrajaya Lake, Malaysia

Sorayya M, Aishah S, Mohd. Sapiyan B

Sains Malaysiana, 2012;41:939-947.

Five years of data from 2001 until 2006 of warm unstratified shallow, oligotrophic to mesothropic tropical Putrajaya Lake, Malaysia were used to study pattern discovery and forecasting of the diatom abundance using supervised and unsupervised artificial neural networks. Recurrent artificial neural network (RANN) was used for the supervised artificial neural network and Kohonen Self Organizing Feature Maps (SOM) was used for unsupervised artificial neural network. RANN was applied for forecasting of diatom abundance. The RANN performance was measured in terms of root mean square error (RMSE) and the value reported was 29.12 cell/mL. Classification and clustering by SOM and sensitivity analysis from the RANN were used to reveal the relationship among water temperature, pH, nitrate nitrogen (NO3-N) concentration, chemical oxygen demand (COD) concentration and diatom abundance. The results indicated that the combination of supervised and unsupervised artificial neural network is important not only for forecasting algae abundance but also in reasoning and understanding ecological relationships. This in return will assist in better management of lake water quality.

Matched MeSH terms: Temperature

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