Displaying publications 1 - 20 of 240 in total

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  1. Zzaman, W., Issara, U., Febrianto, N.F., Yang, T.A.
    International Food Research Journal, 2014;21(3):10191-1023.
    MyJurnal
    The study was conducted to investigate fatty acid composition, rheological properties and crystal formation of rambutan fat and cocoa butter. The results showed that lauric acid, palmitic acid, and stearic fatty acid in rambutan fat were less than cocoa butter, but oleic acid found almost the same. The crystal formation of cocoa butter was not complex at 25oC, while rambutan fat and their mixture shown complicated network of crystal form. The Newton, Bingham and Casson plastic rheological models was used to describe fat flow in this experiment and the result showed that rambutan fat had higher viscosity than cocoa fat. Based on the results the study recommended that mixture proportion up to 30% rambutan seed fat can be used as a cocoa butter substitute whereas higher proportion completely alters original cocoa butter properties. Therefore, there is feasibility of using the rambutan fat to substitute cocoa butter and the mixtures of the two fats in suitable proportion in chocolate manufacturing.
    Matched MeSH terms: Viscosity
  2. Zhalehrajabi E, Lau KK, Ku Shaari KZ, Zahraee SM, Seyedin SH, Azeem B, et al.
    Materials (Basel), 2019 Jul 20;12(14).
    PMID: 31330846 DOI: 10.3390/ma12142320
    Granulation is an important step during the production of urea granules. Most of the commercial binders used for granulation are toxic and non-biodegradable. In this study, a fully biodegradable and cost-effective starch-based binder is used for urea granulation in a fluidized bed granulator. The effect of binder properties such as viscosity, surface tension, contact angle, penetration time, and liquid bridge bonding force on granulation performance is studied. In addition, the effect of fluidized bed process parameters such as fluidizing air inlet velocity, air temperature, weight of primary urea particles, binder spray rate, and binder concentration is also evaluated using response surface methodology. Based on the results, binder with higher concentration demonstrates higher viscosity and higher penetration time that potentially enhance the granulation performance. The viscous Stokes number for binder with higher concentration is lower than critical Stokes number that increases coalescence rate. Higher viscosity and lower restitution coefficient of urea particles result in elastic losses and subsequent successful coalescence. Statistical analysis indicate that air velocity, air temperature, and weight of primary urea particles have major effects on granulation performance. Higher air velocity increases probability of collision, whereby lower temperature prevents binder to be dried up prior to collision. Findings of this study can be useful for process scale-up and industrial application.
    Matched MeSH terms: Viscosity
  3. Zargar M, Ahmadinia E, Asli H, Karim MR
    J Hazard Mater, 2012 Sep 30;233-234:254-8.
    PMID: 22818590 DOI: 10.1016/j.jhazmat.2012.06.021
    The ageing of the bitumen during storage, mixing, transport and laying on the road, as well as in service life, are the most important problems presented by the use of bitumen in pavements. This paper investigates the possibility of using waste cooking oil (WCO), which is a waste material that pollutes landfills and rivers, as an alternative natural rejuvenating agent for aged bitumen to a condition that resembles the original bitumen. With this target, the physical and chemical properties of the original bitumen, aged bitumen and rejuvenated bitumen were measured and compared by the bitumen binder tests - softening point, penetration, Brookfield viscosity, dynamic shear rheometer and Fourier transform infrared spectroscopy. In addition, the behaviour of the WCO rejuvenated bitumen is investigated and compared with virgin bitumen after using the rolling thin film oven ageing process. In general, the results showed that using 3-4% of WCO the aged bitumen group 40/50 was rejuvenated to a condition that closely resembled the physical, rheological properties of the original bitumen (80/100), however, there was a difference in the tendency to ageing between the WCO rejuvenated bitumen and the virgin bitumen during mixing, transport and laying on the road.
    Matched MeSH terms: Viscosity
  4. Zamram QAZM, Mohsin HF, Mohamad MM, Nor Hazalin NAM, Hamid KA
    Curr Drug Deliv, 2021 Apr 18.
    PMID: 33874872 DOI: 10.2174/1567201818666210419114809
    AIM: Formulating topical products for skin delivery has always been a challenge for pharmaceutical scientists to fulfil good formulation criteria. Despite the challenges, gel-based drug delivery offers some advantages such that it is non-invasive, painless, avoidance of the first-pass metabolism and has satisfactory patient compliance.

    OBJECTIVES: In this study, Chromolaena odorata gel and quercetin gel (bioactive flavonoid compound) were successfully formulated and compared with placebo and conventional wound aid gel. The chromatographic profilling was conducted to screen the presence of phytoconstituents. Subsequently, all formulated gels were subjected to physical characteristic and stability study.

    METHODS: Reverse Phase High-Performance Liquid Chromatography (RP-HPLC) of C.odorata methanolic leaves extract shows a distinct compound separation at retention time 8.4min to 34.8 min at 254nm. All gels were characterised by evaluating their rheological properties including storage modulus, loss modulus and plastic viscosity. Besides, texture analysis was performed to measure the gels' firmness, consistency, cohesiveness, and viscosity index.

    RESULTS: From the observation, C. odorata gel demonstrated better spreadability as compared to the other gels, which acquired less work and favourable to be applied onto the skin. Moreover, C. odorata gel showed no changes in organoleptic properties and proven to be stable after 30 days of accelerated stability study at 40°C ± 2°C with relative humidity (RH) of 75%± 5%.

    CONCLUSION: C. odorata gel has shown to be stable, reflecting the combination of materials used in the formulation, which did not degrade throughout the study. This work suggests the potential of this gel as a vehicle to deliver the active ingredients of C. odorata to the skin, which can be further explored as a topical application in antimicrobial wound management or other skin diseases study.

    Matched MeSH terms: Viscosity
  5. 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: Viscosity
  6. 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: Viscosity
  7. Zainol NA, Ming TS, Darwis Y
    Indian J Pharm Sci, 2015 12 15;77(4):422-33.
    PMID: 26664058 DOI: 10.4103/0250-474x.164785
    Cinnamon leaf oil contains a high percentage of eugenol and has antimicrobial, antioxidant and antiinflammatory properties. However, the undiluted oil can cause irritation to the skin. Therefore, the aims of this study were to develop and evaluate cinnamon leaf oil nanocream using palm oil. Nanocream base was prepared using different ratios of oil, surfactants and water. The surfactant used were mixture of Tween 80:Carbitol or Tween 80:Span 65 at different hydrophile-lipophile balance values. The pseudoternary phase diagrams were constructed to identify the nanocream base areas and the results showed that the nanocream bases using Span 65 as co-surfactant produced bigger cream area. Fifteen formulations using mixtures of Tween 80:Span 65 were further evaluated for accelerated stability test, droplet size, zeta potential, rheological properties and apparent viscosity. The nanocream base which had an average droplet size of 219 nm and had plastic flow with thixotropic behavior was selected for incorporation of 2% cinnamon leaf oil. The nanocream containing cinnamon leaf oil had the average size of 286 nm and good rheological characteristics. The in vitro release study demonstrated that eugenol as the main constituent of cinnamon leaf oil was released for about 81% in 10 h. The short-term stability study conducted for 6 months showed that the cinnamon leaf oil nanocream was stable at a temperature of 25° and thus, cinnamon leaf oil nanocream is a promising natural based preparation to be used for topical application.
    Matched MeSH terms: Viscosity
  8. Zainal Abidin, N.F., Yusoff, A., Ahmad, N.
    MyJurnal
    Octenyl succinic anhydride (OSA) modified sago starch was prepared in order to improve the emulsification properties of native starch. In the present study, the major factors affecting esterification were investigated with respect to OSA concentration, pH and reaction time using response surface methodology (RSM) based on central composite rotatable design (CCRD) to obtain the highest value of degree of substitution (DS). Results shown that the optimum conditions for OSA concentration, pH and reaction time were 5.00%, pH 7.20 and 9.65 h, respectively. At optimum condition, the esterification of sago starch with OSA resulted in DS value of 0.0120. The DS increased linearly with the increase in amount of OSA, whilst pH and reaction time show a curvature trend on the value of DS. The value of DS was found to be significantly affected by all the three variables. The experimental values under optimum condition were in good consistent with the predicted values (0.0131), which suggested that the optimisation by RSM is more efficient process than conventional optimisation.
    Matched MeSH terms: Viscosity
  9. Yusrabbil Amiyati Yusof, Zafarizal Aldrin Azizul Hasan, Azhar Ariffin
    Sains Malaysiana, 2018;47:511-515.
    This paper reports the effects of glyceryl ether specifically mono-tert-butoxypropanediol on oil in water emulsion system.
    Based on 12 HLB value, screening for stable emulsions was carried out without the presence of glyceryl ether. A stable
    emulsion was used as a control. Then the effects of glyceryl ether on the emulsion system were investigated. The emulsions
    prepared were analyzed for stability, viscosity, pH value, particle size, in vitro dermal irritation potential, in vitro ocular
    irritation potential and also moisturizing property. The incorporation of glycerol in the emulsion system was also done
    for comparison. Emulsions with glyceryl ether showed lower viscosity values than emulsions with glycerol. Furthermore,
    the emulsions also exhibited moisturizing property compared to the control emulsion. Glyceryl ether is suitable to be
    used in cosmetic products which require reduced viscosity but retain its skin hydration property.
    Matched MeSH terms: Viscosity
  10. Yusop RM, Unciti-Broceta A, Bradley M
    Bioorg Med Chem Lett, 2012 Sep 15;22(18):5780-3.
    PMID: 22901897 DOI: 10.1016/j.bmcl.2012.07.101
    Variation at the 3' position of fluorescein via Suzuki-Miyaura cross-coupling with aryl and heteroaryl moieties gave a family of anthofluoresceins whose spectroscopic properties were studied. The 1-methylindole derivative gave the highest quantum yield and was observed to behave as a molecular rotor, displaying marked variations in fluorescent intensities with viscosity and offering possible application in cellular sensing and fluorescent polarisation assays.
    Matched MeSH terms: Viscosity
  11. Yusof R, Abdulmalek E, Sirat K, Rahman MB
    Molecules, 2014 Jun 13;19(6):8011-26.
    PMID: 24932572 DOI: 10.3390/molecules19068011
    Density, viscosity and ionic conductivity data sets of deep eutectic solvents (DESs) formed by tetrabutylammonium bromide (TBABr) paired with ethlyene glycol, 1,3-propanediol, 1,5-pentanediol and glycerol hydrogen bond donors (HBDs) are reported. The properties of DES were measured at temperatures between 303 K and 333 K for HBD percentages of 66.7% to 90%. The effects of HBDs under different temperature and percentages are systematically analyzed. As expected, the measured density and viscosity of the studied DESs decreased with an increase in temperature, while ionic conductivity increases with temperature. In general, DESs made of TBABr and glycerol showed the highest density and viscosity and the lowest ionic conductivity when compared to other DESs. The presence of an extra hydroxyl group on glycerol in a DES affected the properties of the DES.
    Matched MeSH terms: Viscosity
  12. Yasin MH, Ishak A, Pop I
    Sci Rep, 2015;5:17848.
    PMID: 26647651 DOI: 10.1038/srep17848
    The steady two-dimensional stagnation-point flow and heat transfer past a permeable stretching/shrinking sheet with effects of viscous dissipation, Joule heating and partial velocity slip in the presence of a magnetic field is investigated. The partial differential equations are reduced to nonlinear ordinary differential equations by using a similarity transformation, before being solved numerically by shooting technique. Results indicate that the skin friction coefficient and the local Nusselt number increase as magnetic parameter increases. It is found that for the stretching sheet the solution is unique while for the shrinking sheet there exist nonunique solutions (dual solutions) in certain range of parameters. The stability analysis shows that the upper branch solution is stable while the lower branch solution is unstable.
    Matched MeSH terms: Viscosity
  13. Yap WB, Tey BT, Alitheen NB, Tan WS
    J Chromatogr A, 2010 May 21;1217(21):3473-80.
    PMID: 20388569 DOI: 10.1016/j.chroma.2010.03.012
    Hepatitis B core antigen (HBcAg) is used as a diagnostic reagent for the detection of hepatitis B virus infection. In this study, immobilized metal affinity-expanded bed adsorption chromatography (IMA-EBAC) was employed to purify N-terminally His-tagged HBcAg from unclarified bacterial homogenate. Streamline Chelating was used as the adsorbent and the batch adsorption experiment showed that the optimal binding pH of His-tagged HBcAg was 8.0 with a binding capacity of 1.8 mg per ml of adsorbent. The optimal elution condition for the elution of His-tagged HBcAg from the adsorbent was at pH 7 in the presence of 500 mM imidazole and 1.5 M NaCl. The IMA-EBAC has successfully recovered 56% of His-tagged HBcAg from the unclarified E. coli homogenate with a purification factor of 3.64. Enzyme-linked immunosorbent assay (ELISA) showed that the antigenicity of the recovered His-tagged HBcAg was not affected throughout the IMA-EBAC purification process and electron microscopy revealed that the protein assembled into virus-like particles (VLP).
    Matched MeSH terms: Viscosity
  14. Yap AU, Ong JE, Yahya NA
    J Mech Behav Biomed Mater, 2021 01;113:104120.
    PMID: 33086137 DOI: 10.1016/j.jmbbm.2020.104120
    OBJECTIVES: This study determined the effects of self-adhesive resin coatings on viscoelastic properties of highly viscous glass ionomer cements (HVGICs) using dynamic mechanical analysis.

    MATERIALS AND METHODS: The HVGICs evaluated were Zirconomer [ZR] (Shofu), Equia Forte [EQ] (GC) and Riva [RV] (SDI). Sixty specimens (12mm x 2mm x 2mm) of each material were fabricated using customized Teflon molds. After initial set, the specimens were removed from their molds, finished, measured and randomly divided into 3 groups of 20. Half the specimens in each group were left uncoated while the remaining half was covered with the respective manufacturers' resin coating. The specimens were subsequently conditioned in distilled water, artificial saliva or citric acid at 37°C for 7 days. The uncoated and coated specimens (n=10) were then subjected to dynamic mechanical testing in flexure mode at 37°C with a frequency of 0.1 to 10Hz. Storage modulus, loss modulus and loss tangent data were subjected to normality testing and statistical analysis using one-way ANOVA/Scheffe's post-hoc test and Ttest at significance level p<0.05.

    RESULTS: Mean storage modulus ranged from 1.39 ± 0.36 to 10.80 ± 0.86 GPa while mean loss modulus varied from 0.13 ± 0.03 to 0.70 ± 0.14 GPa after conditioning in the different mediums. Values for loss tangent ranged from 39.4 ± 7.75 to 213.2 ± 20.11 (x10 -3 ). Significant differences in visco-elastic properties were observed between mediums and materials. When conditioned in distilled water and artificial saliva,storage modulus was significantly improved when ZR, EQ and RV were uncoated. Significantly higher values were, however, observed with resin coating when the materials were exposed to citric acid.

    CONCLUSION: The visco-elastic properties of HVGICs were influenced by both resin coating and chemical environment.

    Matched MeSH terms: Viscosity
  15. Yang J, Qiu C, Li G, Lee WJ, Tan CP, Lai OM, et al.
    Food Chem, 2020 Oct 15;327:127014.
    PMID: 32434126 DOI: 10.1016/j.foodchem.2020.127014
    The influence of diacylglycerol (DAG) combined with polyglycerol polyricinoleate (PGPR) on the stability of water-in-oil (W/O) emulsions containing hydrogenated palm oil (HPO) was studied. Polarized light microscope revealed that DAG promoted HPO to crystallize at the water-oil interface, providing the combination of Pickering and network stabilization effects. It was proposed that the molecular compatibility of fatty acids in DAG with HPO accounted for the promotional effect. The interfacial crystallization of DAG together with the surface activity of PGPR led to the formation of emulsions with uniform small droplets and high freeze-thaw stability. Further exploration of physical properties indicated that the combination of DAG and PGPR dramatically improved the emulsion's viscoelasticity and obtained a larger deformation yield. Water droplets in DAG-based emulsions acted as active fillers to improve the network rigidity. Therefore, DAG is a promising material to be used as emulsifier to enhance the physical stability of W/O emulsions.
    Matched MeSH terms: Viscosity
  16. Yakubu R, Peh KK, Tan YT
    Drug Dev Ind Pharm, 2009 Dec;35(12):1430-8.
    PMID: 19929202 DOI: 10.3109/03639040902988566
    The purpose of this study was to design a 24-hour controlled porosity osmotic pump system that utilizes polyvinyl pyrrolidone (PVP) as an osmotic-suspending/release retarding agent of drugs.
    Matched MeSH terms: Viscosity
  17. Yahaya Shagaiya Daniel, Zainal Abdul Aziz, Zuhaila Ismail, Faisal Salah
    MATEMATIKA, 2018;34(2):393-417.
    MyJurnal
    Analyzed the effects of thermal radiation, chemical reaction, heat gener-
    ation/absorption, magnetic and electric fields on unsteady flow and heat transfer of
    nanofluid. The transport equations used passively controlled. A similarity solution is
    employed to transformed the governing equations from partial differential equations to
    a set of ordinary differential equations, and then solve using Keller box method. It was
    found that the temperature is a decreasing function with the thermal stratification due to
    the fact the density of the fluid in the lower vicinity is much higher compared to the upper
    region, whereas the thermal radiation, viscous dissipation and heat generation enhanced
    the nanofluid temperature and thermal layer thickness.
    Matched MeSH terms: Viscosity
  18. Yaacob EN, Goethals J, Bajek A, Dierckens K, Bossier P, De Geest BG, et al.
    Mar Biotechnol (NY), 2017 Aug;19(4):391-400.
    PMID: 28643227 DOI: 10.1007/s10126-017-9758-4
    Aquaculture is the fastest growing animal production sector. However, the production of marine fish is still hampered by the high mortality rate in the first few weeks after hatching. Mortality in larvae is often caused by microbial infections. Today, the incorporation of immunostimulants into microparticles provides us new tools to enhance disease resistance in marine larviculture. In this study, we prepared alginate microparticles loaded with the model antigen fluorescein isothiocyanate conjugated-bovine serum albumin. Optimum concentrations of alginate and CaCl2, the correct alginate viscosity and the appropriate preparatory conditions led to the creation of desirable microparticles with the correct size for oral feeding in gnotobiotic European sea bass larvae. The prepared alginate microparticles were stable in sea water and were successfully ingested by gnotobiotic sea bass larvae at day after hatching 7 without causing any negative effects. Results suggest the suitability of this drug delivery system for targeting the innate immune system of fish larvae in order to enhance disease resistance and thus reduce mortality in larviculture.
    Matched MeSH terms: Viscosity
  19. Wsoo MA, Razak SIA, Bohari SPM, Shahir S, Salihu R, Kadir MRA, et al.
    Int J Biol Macromol, 2021 Jun 30;181:82-98.
    PMID: 33771547 DOI: 10.1016/j.ijbiomac.2021.03.108
    Vitamin D deficiency is now a global health problem; despite several drug delivery systems for carrying vitamin D due to low bioavailability and loss bioactivity. Developing a new drug delivery system to deliver vitamin D3 is a strong incentive in the current study. Hence, an implantable drug delivery system (IDDS) was developed from the electrospun cellulose acetate (CA) and ε-polycaprolactone (PCL) nanofibrous membrane, in which the core of implants consists of vitamin D3-loaded CA nanofiber (CAVD) and enclosed in a thin layer of the PCL membrane (CAVD/PCL). CA nanofibrous mat loaded with vitamin D3 at the concentrations of 6, 12, and 20% (w/w) of vitamin D3 were produced using electrospinning. The smooth and bead-free fibers with diameters ranged from 324 to 428 nm were obtained. The fiber diameters increased with an increase in vitamin D3 content. The controlled drug release profile was observed over 30-days, which fit with the zero-order model (R2 > 0.96) in the first stage. The mechanical properties of IDDS were improved. Young's modulus and tensile strength of CAVD/PCL (dry) were161 ± 14 and 13.07 ± 2.5 MPa, respectively. CA and PCL nanofibers are non-cytotoxic based on the results of the in-vitro cytotoxicity studies. This study can further broaden in-vivo study and provide a reference for developing a new IDDS to carry vitamin D3 in the future.
    Matched MeSH terms: Viscosity
  20. Wong TW, Sumiran N, Mokhtar MT, Kadir A
    Pharm Biol, 2012 Nov;50(11):1463-6.
    PMID: 22889006 DOI: 10.3109/13880209.2012.679985
    In oral insulin delivery, blood glucose profiles of a subject can be a function of complicated transfer of water and insulin between gastrointestinal and blood compartments.
    Matched MeSH terms: Viscosity
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