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  1. Fulltext Kinetic modeling of bacteriocin-like inhibitory substance secretion by Pediococcus acidilactici Kp10 and its stability in food manufacturing conditions
    Abbasiliasi S, Tan JS, Ibrahim TAT, Ramanan RN, Kadkhodaei S, Mustafa S, et al.
    J Food Sci Technol, 2018 Apr;55(4):1270-1284.
    PMID: 29606741 DOI: 10.1007/s13197-018-3037-x
    This paper deliberates the modelling and validation of bacteriocin-like inhibitory substance (BLIS) secretion by Pediococcus acidilactici Kp10 at different agitation speeds in a stirred tank bioreactor. A range of models namely the re-parameterised logistic, Luedeking-Piret and maintenance energy were assessed to predict the culture performance of the said bacterium. Growth of P. acidilactici Kp10 was enhanced with increased agitation speed up to 600 rpm while BLIS secretion was maximum at 400 rpm but decreased at higher agitation speed. Growth of P. acidilactici aptly subscribed to the re-parameterised logistic model while BLIS secretion and lactose consumption fitted well with the Luedeking-Piret model. The models revealed a relationship between growth of the bacterium and BLIS secretion. Bacterial growth and BLIS secretion were largely affected by the agitation speed of the stirred tank bioreactor which regulated the oxygen transfer to the culture. BLIS secretion by P. acidilactici Kp10 was however enhanced in oxygen-limited culture. The study also assessed BLIS from the perspective of its stability when subjected to factors such as temperature, pH and detergents. Results showed that BLIS produced by this strain was not affected by heat (at 25-100 °C for 20 min and at 121 °C for 15 min), surfactant (Tween 40, 60 and 80 and urea), detergents (up to 1% SDS), organic solvents (50% each of acetone, methanol and ethanol) and stable in a wide range of pH (2-10). The above information are pertinent with reference to commercial applications of this bacterial product in food manufacturing which invariably involve various sterilization processes and subjected to a wide pH range.
    Matched MeSH terms: Hot Temperature
  2. Formation and reduction of 5-hydroxymethylfurfural at frying temperature in model system as a function of amino acid and sugar composition
    Kavousi P, Mirhosseini H, Ghazali H, Ariffin AA
    Food Chem, 2015 Sep 1;182:164-70.
    PMID: 25842323 DOI: 10.1016/j.foodchem.2015.02.135
    5-Hydroxymethylfurfural (HMF) is formed during heat treatment of carbohydrate-containing foods, especially in a deep-fat frying process. This study aimed to investigate the effect of amino acids on the formation and reduction of HMF from glucose, fructose and sucrose at frying temperature in model systems containing binary mixtures of an amino acid and a sugar in equal concentrations (0.3M). The results revealed that the formation of HMF from sugars accelerated in the presence of acidic amino acids (i.e. glutamic and aspartic acids). Conversely, the presence of basic amino acids (i.e. lysine, arginine and histidine) led to reduced concentrations of HMF to non-detectable levels in model systems. The results showed that both pH and heating time significantly affected the formation of HMF from fructose in the presence of glutamic acid. In this regard, a higher amount of HMF was formed at lower pH.
    Matched MeSH terms: Hot Temperature*
  3. Fulltext Functionality of Cellulose Nanofiber as Bio-Based Nucleating Agent and Nano-Reinforcement Material to Enhance Crystallization and Mechanical Properties of Polylactic Acid Nanocomposite
    Shazleen SS, Yasim-Anuar TAT, Ibrahim NA, Hassan MA, Ariffin H
    Polymers (Basel), 2021 Jan 27;13(3).
    PMID: 33513688 DOI: 10.3390/polym13030389
    Polylactic acid (PLA), a potential alternative material for single use plastics, generally portrays a slow crystallization rate during melt-processing. The use of a nanomaterial such as cellulose nanofibers (CNF) may affect the crystallization rate by acting as a nucleating agent. CNF at a certain wt.% has been evidenced as a good reinforcement material for PLA; nevertheless, there is a lack of information on the correlation between the amount of CNF in PLA that promotes its functionality as reinforcement material, and its effect on PLA nucleation for improving the crystallization rate. This work investigated the nucleation effect of PLA incorporated with CNF at different fiber loading (1-6 wt.%) through an isothermal and non-isothermal crystallization kinetics study using differential scanning calorimetry (DSC) analysis. Mechanical properties of the PLA/CNF nanocomposites were also investigated. PLA/CNF3 exhibited the highest crystallization onset temperature and enthalpy among all the PLA/CNF nanocomposites. PLA/CNF3 also had the highest crystallinity of 44.2% with an almost 95% increment compared to neat PLA. The highest crystallization rate of 0.716 min-1 was achieved when PLA/CNF3 was isothermally melt crystallized at 100 °C. The crystallization rate was 65-fold higher as compared to the neat PLA (0.011 min-1). At CNF content higher than 3 wt.%, the crystallization rate decreased, suggesting the occurrence of agglomeration at higher CNF loading as evidenced by the FESEM micrographs. In contrast to the tensile properties, the highest tensile strength and Young's modulus were recorded by PLA/CNF4 at 76.1 MPa and 3.3 GPa, respectively. These values were, however, not much different compared to PLA/CNF3 (74.1 MPa and 3.3 GPa), suggesting that CNF at 3 wt.% can be used to improve both the crystallization rate and the mechanical properties. Results obtained from this study revealed the dual function of CNF in PLA nanocomposite, namely as nucleating agent and reinforcement material. Being an organic and biodegradable material, CNF has an increased advantage for use in PLA as compared to non-biodegradable material and is foreseen to enhance the potential use of PLA in single use plastics applications.
    Matched MeSH terms: Hot Temperature
  4. Unsteady free convection flow between two vertical parallel plates with newtonian heating
    Fasihah Zulkiflee, Ahmad Qushairi Mohamad, Sharidan Shafie, Arshad Khan
    MATEMATIKA, 2019;35(2):117-127.
    MyJurnal
    Free convection flow in a boundary layer region is a motion that results from the interaction of gravity with density differences within a fluid. These differences occur due to temperature or concentration gradients or due to their composition. Studies per- taining free convection flows of incompressible viscous fluids have received much attention in recent years both theoretically (exact or approximate solutions) and experimentally. The situation where the heat be transported to the convective fluid via a bounding sur- face having finite heat capacity is known as Newtonian heating (or conjugate convective flows). In this paper, the unsteady free convection flow of an incompressible viscous fluid between two parallel plates with Newtonian heating is studied. Appropriate non- dimensional variables are used to reduce the dimensional governing equations along with imposed initial and boundary conditions into dimensionless forms. The exact solutions for velocity and temperature are obtained using the Laplace transform technique. The corresponding expressions for skin friction and Nusselt number are also calculated. The graphical results are displayed to illustrate the influence of various embedded parameters such as Newtonian heating parameter and Grashof number. The results show that the effect of Newtonian heating parameter increases the Nusselt number but reduces the skin friction.
    Matched MeSH terms: Hot Temperature
  5. Fulltext Thermo-mechanical contact problems and elastic behaviour of single and double sides functionally graded brake disks with temperature-dependent material properties
    Bayat M, Alarifi IM, Khalili AA, El-Bagory TMAA, Nguyen HM, Asadi A
    Sci Rep, 2019 Oct 25;9(1):15317.
    PMID: 31653877 DOI: 10.1038/s41598-019-51450-z
    A thermo-elastic contact problem of functionally graded materials (FGMs) rotating brake disk with different pure brake pad areas under temperature dependent material properties is solved by Finite Element Method (FEM). The properties of brake disk change gradually from metal to ceramic by power-law distribution along the radial direction from the inner to the outer surface. Areas of the pure pad are changing while the vertical force is constant. The ratio of brake pad thickness to FGMs brake disk thickness is assumed 0.66. Two sources of thermal loads are considered: (1) Heat generation between the pad and brake disk due to contact friction, and (2) External thermal load due to a constant temperature at inner and outer surfaces. Mechanical responses of FGMs disk are compared with several pad contact areas. The results for temperature-dependent and temperature-independent material properties are investigated and presented. The results show that the absolute value of the shear stress in temperature-dependent material can be greater than that for temperature-independent material. The radial stress for some specific grading index (n = 1.5) is compressive near the inner surface for double contact while it is tensile for a single contact. It is concluded that the radial strain for some specific value of grading index (n = 1) is lower than other FGMs and pure double side contact brake disks.
    Matched MeSH terms: Hot Temperature
  6. Fulltext Enrichment of Eucalyptus oil nanoemulsion by micellar nanotechnology: transdermal analgesic activity using hot plate test in rats' assay
    Aziz ZAA, Nasir HM, Ahmad A, Setapar SHM, Ahmad H, Noor MHM, et al.
    Sci Rep, 2019 Sep 23;9(1):13678.
    PMID: 31548590 DOI: 10.1038/s41598-019-50134-y
    Eucalyptus globulus is an aromatic medicinal plant which known for its 1,8-cineole main pharmacological constituent exhibits as natural analgesic agent. Eucalyptus globulus-loaded micellar nanoparticle was developed via spontaneous emulsification technique and further evaluation for its analgesic efficacy study, in vivo analgesic activity assay in rats. The nanoemulsion system containing Eucalyptus-micelles was optimized at different surfactant types (Tween 40, 60 and 80) and concentrations (3.0, 6.0, 9.0, 12.0, 15.0, and 18.0 wt. %). These formulations were characterized by thermodynamically stability, viscosity, micelles particle size, pH, and morphology structure. The spontaneous emulsification technique offered a greener micelles formation in nanoemulsion system by slowly titrated of organic phase, containing Eucalyptus globulus (active compound), grape seed oil (carrier oil) and hydrophilic surfactant into aqueous phase, and continuously stirred for 30 min to form a homogeneity solution. The characterizations evaluation revealed an optimized formulation with Tween 40 surfactant type at 9.0 wt. % of surfactant concentration promoted the most thermodynamic stability, smaller micelles particle size (d = 17.13 ± 0.035 nm) formed with spherical shape morphological structure, and suitable in viscosity (≈2.3 cP) and pH value (6.57) for transdermal purpose. The in vivo analgesic activity assay of optimized emulsion showed that the transdermal administration of micellar nanoparticle of Eucalyptus globulus on fore and hind limb of rats, possessed the central and peripheral analgesic effects by prolonged the rats pain responses towards the heat stimulus after being put on top of hot plate (55 °C), with longest time responses, 40.75 s at 60 min after treatment administration. Thus, this study demonstrated that micellar nanoparticle of Eucalyptus globulus formed in nanoemulsion system could be promising as an efficient transdermal nanocarrier for the analgesic therapy alternative.
    Matched MeSH terms: Hot Temperature
  7. Fulltext The non-Newtonian maxwell nanofluid flow between two parallel rotating disks under the effects of magnetic field
    Ahmadian A, Bilal M, Khan MA, Asjad MI
    Sci Rep, 2020 Oct 13;10(1):17088.
    PMID: 33051520 DOI: 10.1038/s41598-020-74096-8
    The main feature of the present numerical model is to explore the behavior of Maxwell nanoliquid moving within two horizontal rotating disks. The disks are stretchable and subjected to a magnetic field in axial direction. The time dependent characteristics of thermal conductivity have been considered to scrutinize the heat transfer phenomena. The thermophoresis and Brownian motion features of nanoliquid are studied with Buongiorno model. The lower and upper disk's rotation for both the cases, same direction as well as opposite direction of rotation is investigated. The subsequent arrangement of the three dimensional Navier Stoke's equations along with energy, mass and Maxwell equations are diminished to a dimensionless system of equations through the Von Karman's similarity framework. The comparative numerical arrangement of modeled equations is further set up by built-in numerical scheme "boundary value solver" (Bvp4c) and Runge Kutta fourth order method (RK4). The various physical constraints, such as Prandtl number, thermal conductivity, magnetic field, thermal radiation, time relaxation, Brownian motion and thermophoresis parameters and their impact are presented and discussed briefly for velocity, temperature, concentration and magnetic strength profiles. In the present analysis, some vital characteristics such as Nusselt and Sherwood numbers are considered for physical and numerical investigation. The outcomes concluded that the disk stretching action opposing the flow behavior. With the increases of magnetic field parameter [Formula: see text] the fluid velocity decreases, while improving its temperature. We show a good agreement of the present work by comparing with those published in literature.
    Matched MeSH terms: Hot Temperature
  8. Fulltext Numerical analysis of thermal conductive hybrid nanofluid flow over the surface of a wavy spinning disk
    Ahmadian A, Bilal M, Khan MA, Asjad MI
    Sci Rep, 2020 Nov 02;10(1):18776.
    PMID: 33139760 DOI: 10.1038/s41598-020-75905-w
    A three dimensional (3D) numerical solution of unsteady, Ag-MgO hybrid nanoliquid flow with heat and mass transmission caused by upward/downward moving of wavy spinning disk has been scrutinized. The magnetic field has been also considered. The hybrid nanoliquid has been synthesized in the presence of Ag-MgO nanoparticles. The purpose of the study is to improve the rate of thermal energy transmission for several industrial purposes. The wavy rotating surface increases the heat transmission rate up to 15%, comparatively to the flat surface. The subsequent arrangement of modeled equations is diminished into dimensionless differential equation. The obtained system of equations is further analytically expounded via Homotopy analysis method HAM and the numerical Parametric continuation method (PCM) method has been used for the comparison of the outcomes. The results are graphically presented and discussed. It has been presumed that the geometry of spinning disk positively affects the velocity and thermal energy transmission. The addition of hybrid nanoparticles (silver and magnesium-oxide) significantly improved thermal property of carrier fluid. It uses is more efficacious to overcome low energy transmission. Such as, it provides improvement in thermal performance of carrier fluid, which play important role in power generation, hyperthermia, micro fabrication, air conditioning and metallurgical field.
    Matched MeSH terms: Hot Temperature
  9. Fulltext Thermal profiling Analysis for Asymmetrically Embedded Tumour with Different Breast Densities
    Laila Fadhillah Ulta Delestri, Kenshiro Ito, Gan Hong Seng, Muhammad Faiz Md Shakhih, Asnida Abdul Wahab
    Malaysian Journal of Medicine and Health Sciences, 2020;16(108):6-12.
    MyJurnal
    Introduction: Detecting breast cancer at earlier stage is crucial to increase the survival rate. Mammography as the golden screening tool has shown to be less effective for younger women due to denser breast tissue. Infrared Ther- mography has been touted as an adjunct modality to mammography. Further investigation of thermal distribution in breast cancer patient is important prior to its clinical interpretation. Therefore, thermal profiling using 3D compu- tational simulation was carried out to understand the effect of changes in size and location of tumour embedded in breast to the surface temperature distribution at different breast densities. Methods: Extremely dense (ED) and pre- dominantly fatty dense (PF) breast models were developed and simulated using finite element analysis (FEA). Pennes’ bioheat equation was adapted to show the heat transfer mechanism by providing appropriate thermophysical prop- erties in each tissue layer. 20 case studies with various tumour size embedded at two asymmetrical positions in the breast models were analysed. Quantitative and qualitative analyses were performed by recording the temperature values along the arc of breast, calculating of temperature difference at the peaks and comparing multiple thermal images. Results: Bigger size of tumour demands a larger increase in breast surface temperatures. As tumour is located far from the centre of the breast or near to the edge, there was a greater shift of temperature peak. Conclusion: Size and location of tumour in various levels of breast density should be considered as a notable factor to thermal profile on breast when using thermography for early breast cancer detection.
    Matched MeSH terms: Hot Temperature
  10. Fulltext Double Pulse Resistance Spot Welding of Dual Phase Steel: Parametric Study on Microstructure, Failure Mode and Low Dynamic Tensile Shear Properties
    Soomro IA, Pedapati SR, Awang M
    Materials (Basel), 2021 Feb 08;14(4).
    PMID: 33567606 DOI: 10.3390/ma14040802
    Resistance spot welding (RSW) of dual phase (DP) steels is a challenging task due to formation of brittle martensitic structure in the fusion zone (FZ), resulting in a low energy capacity of the joint during high-rate loading. In the present study, in situ postweld heat treatment (PWHT) was carried out by employing a double pulse welding scheme with the aim of improving the mechanical performance of DP590 steel resistance spot weld joint. Taguchi method was used to optimize in situ PWHT parameters to obtain maximum peak load and failure energy. Experiments were designed based on orthogonal array (OA) L16. Mechanical performance was evaluated in terms of peak load and failure energy after performing low dynamic tensile shear (TS) test. Microstructural characterization was carried out using a scanning electron microscope (SEM). The results show that improvements of 17 and 86% in peak load and failure energy, respectively, were achieved in double-pulse welding (DPW) at optimum conditions compared to traditional single-pulse welding (SPW). The improvement in mechanical performance resulted from (i) enlargement of the FZ and (ii) improved weld toughness due to tempering of martensite in the FZ and subcritical heat affected zone (SCHAZ). These factors are influenced by heat input, which in turn depends upon in situ PWHT parameters.
    Matched MeSH terms: Hot Temperature
  11. Fulltext Physicochemical, pasting and gel textural properties of wheat-ripe Cavendish banana composite flours
    Ng, K. F., Abbas, F. M. A., Tan, T. C., Azhar, M. E.
    International Food Research Journal, 2014;21(2):655-662.
    MyJurnal
    Proximate composition, pH and amylose content of ripe Cavendish banana flour (RBF) prepared in this study were compared with all-purpose wheat flour (WF). RBF was found to be significantly (P < 0.05) higher in total carbohydrates and minerals content, while significantly (P < 0.05) lower in protein and fat contents compared with those of WF. Wheat-ripe banana composite flours (W-RBF) prepared by partial substitution of WF with RBF were assessed for swelling power, solubility, pasting properties and gel textural properties. Granular swelling of RBF occurred at a higher temperature compared to that of WF, suggesting that more energy and water were required to cook WF-RBF as the presence of soluble carbohydrates would compete for water and this would eventually delay starch hydration and granular expansion during cooking. Higher substitution with RBF led to higher soluble carbohydrates content, and increase in solubility index of WF-RBF. Partial substitution with RBF also resulted in significant (P < 0.05) decrease in pasting properties. A higher substitution of WF with RBF could reduce starch gelatinisation during cooking and retrogradation owing to the reduction of available starch in WF-RBF. All WF-RBF gels were significantly (P < 0.05) firmer and less sticky compared to WF gels.
    Matched MeSH terms: Hot Temperature
  12. Studies on the effects of titanate and silane coupling agents on the performance of poly (methyl methacrylate)/barium titanate denture base nanocomposites
    Elshereksi NW, Ghazali MJ, Muchtar A, Azhari CH
    J Dent, 2017 Jan;56:121-132.
    PMID: 27916635 DOI: 10.1016/j.jdent.2016.11.012
    OBJECTIVES: This study aimed to fabricate and characterise silanated and titanated nanobarium titanate (NBT) filled poly(methyl methacrylate) (PMMA) denture base composites and to evaluate the behaviour of a titanate coupling agent (TCA) as an alternative coupling agent to silane. The effect of filler surface modification on fracture toughness was also studied.

    METHODS: Silanated, titanated and pure NBT at 5% were incorporated in PMMA matrix. Neat PMMA matrix served as a control. NBT was sonicated in MMA prior to mixing with the PMMA. Curing was carried out using a water bath at 75°C for 1.5h and then at 100°C for 30min. NBT was characterised via Fourier transform-infrared spectroscopy (FTIR), Transmission Electron Microscopy (TEM) and Brunauer-Emmett-Teller (BET) analysis before and after surface modification. The porosity and fracture toughness of the PMMA nanocomposites (n=6, for each formulation and test) were also evaluated.

    RESULTS: NBT was successfully functionalised by the coupling agents. The TCA exhibited the lowest percentage of porosity (0.09%), whereas silane revealed 0.53% porosity. Statistically significant differences in fracture toughness were observed among the fracture toughness values of the tested samples (p<0.05). While the fracture toughness of untreated samples was reduced by 8%, an enhancement of 25% was achieved after titanation. In addition, the fracture toughness of the titanated samples was higher than the silanated ones by 10%.

    CONCLUSION: Formation of a monolayer on the surface of TCA enhanced the NBT dispersion, however agglomeration of silanated NBT was observed due to insufficient coverage of NBT surface. Such behaviour led to reducing the porosity level and improving fracture toughness of titanated NBT/PMMA composites. Thus, TCA seemed to be more effective than silane.

    CLINICAL SIGNIFICANCE: Minimising the porosity level could have the potential to reduce fungus growth on denture base resin to be hygienically accepTable Such enhancements obtained with Ti-NBT could lead to promotion of the composites' longevity.

    Matched MeSH terms: Hot Temperature
  13. Fulltext Knowledge, Attitude, Exposure, and Future Intentions toward Exclusive Breastfeeding among Universiti Sains Malaysia Final Year Medical and Dental Students
    Mohamad N, Saddki N, Azman KNK, Aziz IDA
    Korean J Fam Med, 2019 Jul;40(4):261-268.
    PMID: 30625269 DOI: 10.4082/kjfm.18.0021
    BACKGROUND: Breastmilk is the best nourishment for an infant for the first 6 months of life. Health professionals like medical doctors and dentists can help promote and support exclusive breastfeeding. We aimed to assess knowledge, attitudes, exposure, and future intentions toward exclusive breastfeeding among final year medical and dental students at Universiti Sains Malaysia, Kelantan, Malaysia.

    METHODS: A total of 162 students participated in this cross-sectional study that was conducted between May and September of 2015. Self-administered questionnaires were used to collect the variables of interest.

    RESULTS: Most students knew exclusive breastfeeding is recommended for the first 6 months of life (98.1%). However, some students incorrectly thought formula milk can be given if the infant appears hungry after having been breastfed (61.7%). Additionally, some incorrectly thought expressed breastmilk can be warmed on direct heat (47.5%) and left-over expressed milk can be re-stored (60.5%). Most students agreed that exclusive breastfeeding is easier to practice than formula feeding and that it is the best choice for working mothers. Most students (93.2%) intend to breastfeed their children, and this intention was significantly associated with their experience being breastfed as infants and attitudes toward exclusive breastfeeding.

    CONCLUSION: Generally, final year medical and dental students have favorable attitudes and future intentions toward exclusive breastfeeding, although some of them lacked knowledge about certain important aspects of the practice. Past experience of being exclusively breastfed and a more positive attitude toward the practice were associated with their future intentions to practice exclusive breastfeeding.

    Matched MeSH terms: Hot Temperature
  14. Fulltext Strength Development and Elemental Distribution of Dolomite/Fly Ash Geopolymer Composite under Elevated Temperature
    Azimi EA, Abdullah MMAB, Vizureanu P, Salleh MAAM, Sandu AV, Chaiprapa J, et al.
    Materials (Basel), 2020 Feb 24;13(4).
    PMID: 32102345 DOI: 10.3390/ma13041015
    A geopolymer has been reckoned as a rising technology with huge potential for application across the globe. Dolomite refers to a material that can be used raw in producing geopolymers. Nevertheless, dolomite has slow strength development due to its low reactivity as a geopolymer. In this study, dolomite/fly ash (DFA) geopolymer composites were produced with dolomite, fly ash, sodium hydroxide, and liquid sodium silicate. A compression test was carried out on DFA geopolymers to determine the strength of the composite, while a synchrotron Micro-Xray Fluorescence (Micro-XRF) test was performed to assess the elemental distribution in the geopolymer composite. The temperature applied in this study generated promising properties of DFA geopolymers, especially in strength, which displayed increments up to 74.48 MPa as the optimum value. Heat seemed to enhance the strength development of DFA geopolymer composites. The elemental distribution analysis revealed exceptional outcomes for the composites, particularly exposure up to 400 °C, which signified the homogeneity of the DFA composites. Temperatures exceeding 400 °C accelerated the strength development, thus increasing the strength of the DFA composites. This appears to be unique because the strength of ordinary Portland Cement (OPC) and other geopolymers composed of other raw materials is typically either maintained or decreases due to increased heat.
    Matched MeSH terms: Hot Temperature
  15. LC-MS/MS-based metabolites of Eurycoma longifolia (Tongkat Ali) in Malaysia (Perak and Pahang)
    Chua LS, Amin NA, Neo JC, Lee TH, Lee CT, Sarmidi MR, et al.
    J Chromatogr B Analyt Technol Biomed Life Sci, 2011 Dec 15;879(32):3909-19.
    PMID: 22119436 DOI: 10.1016/j.jchromb.2011.11.002
    A number of three LC-MS/MS hybrid systems (QTof, TripleTof and QTrap) has been used to profile small metabolites (m/z 100-1000) and to detect the targeted metabolites such as quassinoids, alkaloids, triterpene and biphenylneolignans from the aqueous extracts of Eurycoma longifolia. The metabolite profiles of small molecules showed four significant clusters in the principle component analysis for the aqueous extracts of E. longifolia, which had been collected from different geographical terrains (Perak and Pahang) and processed at different extraction temperatures (35°C and 100°C). A small peptide of leucine (m/z 679) and a new hydroxyl methyl β-carboline propionic acid have been identified to differentiate E. longifolia extracts that prepared at 35°C and 100°C, respectively. From the targeted metabolites identification, it was found that 3,4ɛ-dihydroeurycomanone (quassinoids) and eurylene (squalene-type triterpene) could only be detected in the Pahang extract, whereas canthin-6-one-3N-oxide could only be detected in the Perak extract. Overall, quassinoids were present in the highest concentration, particularly eurycomanone and its derivatives compared to the other groups of metabolites. However, the concentration of canthin-6-one and β-carboline alkaloids was significantly increased when the roots of the plant samples were extracted at 100°C.
    Matched MeSH terms: Hot Temperature
  16. Fulltext Flow behaviour and viscoelasticity of polypropylene-kaolin composites extruded at different temperatures
    Nor Azura Abdul Rahim, Zulkifli Mohamad Ariff, Azlan Ariffin
    Pertanika Journal of Science & Technology, 2011;19(2):383-388.
    MyJurnal
    A study of kaolin addition in polypropylene (PP-kaolin) melt was carried out to characterize its flow behaviour and viscoelasticity at different temperatures. The compound of 20 wt% kaolin was prepared by melt mixing using two roll-mill heated at 185°C, while the compounded composites were put through a single screw extruder to evaluate its melt flow properties. The prepared PPKaolin composites exhibited a shear thinning behaviour and appeared to be strongly dependent on temperature. Moreover, it was also found that the power law index was constantly increased as the temperature increased. Meanwhile, a similar trend was observed for swelling ratio, whereby it also increased with increasing temperature. It was also observed that changes in the die temperatures would result in the formation of obvious bubble like surface morphology, and it became more prominent when the temperature was lowered.
    Matched MeSH terms: Hot Temperature
  17. Fulltext Recent Progress on Stability and Thermo-Physical Properties of Mono and Hybrid towards Green Nanofluids
    Zainon SNM, Azmi WH
    Micromachines (Basel), 2021 Feb 11;12(2).
    PMID: 33670250 DOI: 10.3390/mi12020176
    Many studies have shown the remarkable enhancement of thermo-physical properties with the addition of a small quantity of nanoparticles into conventional fluids. However, the long-term stability of the nanofluids, which plays a significant role in enhancing these properties, is hard to achieve, thus limiting the performance of the heat transfer fluids in practical applications. The present paper attempts to highlight various approaches used by researchers in improving and evaluating the stability of thermal fluids and thoroughly explores various factors that contribute to the enhancement of the thermo-physical properties of mono, hybrid, and green nanofluids. There are various methods to maintain the stability of nanofluids, but this paper particularly focuses on the sonication process, pH modification, and the use of surfactant. In addition, the common techniques to evaluate the stability of nanofluids are undertaken by using visual observation, TEM, FESEM, XRD, zeta potential analysis, and UV-Vis spectroscopy. Prior investigations revealed that the type of nanoparticle, particle volume concentration, size and shape of particles, temperature, and base fluids highly influence the thermo-physical properties of nanofluids. In conclusion, this paper summarized the findings and strategies to enhance the stability and factors affecting the thermal conductivity and dynamic viscosity of mono and hybrid of nanofluids towards green nanofluids.
    Matched MeSH terms: Hot Temperature
  18. Fulltext Temperature Measurement System for Building Material and Built Space Thermal Evaluation
    Zainazlan Md Zain1, Mohd Nasir Taib, Shahrizam M. S. Baki, Azni Zain Ahmed
    Scientific Research Journal, 2016;3(1):1-9.
    MyJurnal
    This paper examines the temperature profile of a building material and also a
    built space. The study directly examines the influence of solar radiation on
    building material and the heat it generated and diffuses into the built space.
    Two experiments are presented. The first look at a simple technique for
    evaluating heat performance of a building material, and the second evaluates
    the performance of a cross-ventilated built space with respect to solar radiation.
    Matched MeSH terms: Hot Temperature
  19. A comprehensive review of milk fouling on heated surfaces
    Sadeghinezhad E, Kazi SN, Dahari M, Safaei MR, Sadri R, Badarudin A
    Crit Rev Food Sci Nutr, 2015;55(12):1724-43.
    PMID: 24731003 DOI: 10.1080/10408398.2012.752343
    Heat exchanger performance degrades rapidly during operation due to formation of deposits on heat transfer surfaces which ultimately reduces service life of the equipment. Due to scaling, product deteriorates which causes lack of proper heating. Chemistry of milk scaling is qualitatively understood and the mathematical models for fouling at low temperatures have been produced but the behavior of systems at ultra high temperature processing has to be studied further to understand in depth. In diversified field, the effect of whey protein fouling along with pressure drop in heat exchangers were conducted by many researchers. Adding additives, treatment of heat exchanger surfaces and changing of heat exchanger configurations are notable areas of investigation in milk fouling. The present review highlighted information about previous work on fouling, influencing parameters of fouling and its mitigation approach and ends up with recommendations for retardation of milk fouling and necessary measures to perform the task.
    Matched MeSH terms: Hot Temperature*
  20. Fulltext Food and water-borne protozoal diseases (FWBPD)
    Baha Latif
    Medical Health Reviews, 2009;2009(2):27-46.
    MyJurnal
    This review places emphasis on the food and water borne protozoal diseases like, cryptosporidiosis, giardiasis, cyclosporiasis, and toxoplasmosis which are endemic in many parts of the world. The article addresses cryptosporidiosis, giardiasis, cyclosporiasis, and toxoplasmosis. Cryptosporidium and Giardia are widespread in the environment and major outbreaks have occurred as a result of contaminated drinking water. Cyclospora has significance in the preparation and consumption of fresh food that have not received heat treatment. Toxoplasma gondii, transmission occur through contaminated water, unpasteurised milk and also the consumption of raw meat, which has been regarded as a major route of transmission to humans .These parasitic protozoa do not multiply in foods, but they may survive in or on moist foods for months especially in cool and damp environment. Their ecology makes control of these parasites difficult. Transmission, clinical manifestations, outbreaks, public health surveillance and control measures that are used for those diseases will be reviewed in this article.
    Matched MeSH terms: Hot Temperature
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