Displaying publications 1 - 20 of 240 in total

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  1. pH dependent poly[2-(methacryloyloxyethyl)trimetylammonium chloride-co-methacrylic acid]hydrogels for enhanced targeted delivery of 5-fluorouracil in colon cancer cells
    Mishra RK, Ramasamy K, Ahmad NA, Eshak Z, Majeed AB
    J Mater Sci Mater Med, 2014 Apr;25(4):999-1012.
    PMID: 24398912 DOI: 10.1007/s10856-013-5132-x
    Stimuli responsive hydrogels have shown enormous potential as a carrier for targeted drug delivery. In this study we have developed novel pH responsive hydrogels for the delivery of 5-fluorouracil (5-FU) in order to alleviate its antitumor activity while reducing its toxicity. We used 2-(methacryloyloxyethyl) trimetylammonium chloride a positively charged monomer and methacrylic acid for fabricating the pH responsive hydrogels. The released 5-FU from all except hydrogel (GEL-5) remained biologically active against human colon cancer cell lines [HT29 (IC50 = 110-190 μg ml(-1)) and HCT116 (IC50 = 210-390 μg ml(-1))] but not human skin fibroblast cells [BJ (CRL2522); IC50 ≥ 1000 μg ml(-1)]. This implies that the copolymer hydrogels (1-4) were able to release 5-FU effectively to colon cancer cells but not normal human skin fibroblast cells. This is probably due to the shorter doubling time that results in reduced pH in colon cancer cells when compared to fibroblast cells. These pH sensitive hydrogels showed well defined cell apoptosis in HCT116 cells through series of events such as chromatin condensation, membrane blebbing, and formation of apoptotic bodies. No cell killing was observed in the case of blank hydrogels. The results showed the potential of these stimuli responsive polymer hydrogels as a carrier for colon cancer delivery.
    Matched MeSH terms: Viscosity
  2. Fulltext g-Jitter mixed convective slip flow of nanofluid past a permeable stretching sheet embedded in a Darcian porous media with variable viscosity
    Uddin MJ, Khan WA, Amin NS
    PLoS One, 2014;9(6):e99384.
    PMID: 24927277 DOI: 10.1371/journal.pone.0099384
    The unsteady two-dimensional laminar g-Jitter mixed convective boundary layer flow of Cu-water and Al2O3-water nanofluids past a permeable stretching sheet in a Darcian porous is studied by using an implicit finite difference numerical method with quasi-linearization technique. It is assumed that the plate is subjected to velocity and thermal slip boundary conditions. We have considered temperature dependent viscosity. The governing boundary layer equations are converted into non-similar equations using suitable transformations, before being solved numerically. The transport equations have been shown to be controlled by a number of parameters including viscosity parameter, Darcy number, nanoparticle volume fraction, Prandtl number, velocity slip, thermal slip, suction/injection and mixed convection parameters. The dimensionless velocity and temperature profiles as well as friction factor and heat transfer rates are presented graphically and discussed. It is found that the velocity reduces with velocity slip parameter for both nanofluids for fluid with both constant and variable properties. It is further found that the skin friction decreases with both Darcy number and momentum slip parameter while it increases with viscosity variation parameter. The surface temperature increases as the dimensionless time increases for both nanofluids. Nusselt numbers increase with mixed convection parameter and Darcy numbers and decreases with the momentum slip. Excellent agreement is found between the numerical results of the present paper with published results.
    Matched MeSH terms: Viscosity
  3. g-Jitter free convection flow of nanofluid in the three-dimensional stagnation point region
    Mohamad Hidayad Ahmad Kamal, Anati Ali, Sharidan Shafie
    MATEMATIKA, 2019;35(2):260-270.
    MyJurnal
    The three dimensional free convection boundary layer flow near a stagnation point region is embedded in viscous nanofluid with the effect of g-jitter is studied in this paper. Copper (Cu) and aluminium oxide (Al2O3) types of water base nanofluid are cho- sen with the constant Prandtl number, Pr=6.2. Based on Tiwari-Das nanofluid model, the boundary layer equation used is converted into a non-dimensional form by adopting non- dimensional variables and is solved numerically by engaging an implicit finite-difference scheme known as Keller-box method. Behaviors of fluid flow such as skin friction and Nusset number are studied by the controlled parameters including oscillation frequency, amplitude of gravity modulation and nanoparticles volume fraction. The reduced skin friction and Nusset number are presented graphically and discussed for different values of principal curvatures ratio at the nodal point. The numerical results shows that, in- crement occurs in the values of Nusset number with the presence of solid nanoparticles together with the values of the skin friction. It is worth mentioning that for the plane stagnation point there is an absence of reduced skin friction along the y-direction where as for axisymmetric stagnation point, the reduced skin friction for both directions are the same. As nanoparticles volume fraction increased, the skin friction increased as well as the Nusset number. The results, indicated that skin frictions of copper are found higher than aluminium oxide.
    Matched MeSH terms: Viscosity
  4. [Modification of blood coagulation through Arwin]
    Vinazzer H
    Subsid Med, 1974;4:53-5.
    PMID: 4450561
    Matched MeSH terms: Blood Viscosity/drug effects
  5. [Effect of Arvin on blood coagulation]
    Vinazzer H
    Wien Z Inn Med, 1971;52(8):378-92.
    PMID: 5110844
    Matched MeSH terms: Blood Viscosity/drug effects
  6. Vitamin D3-loaded electrospun cellulose acetate/polycaprolactone nanofibers: Characterization, in-vitro drug release and cytotoxicity studies
    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
  7. Viscosity effects of polyvinyl siloxane impression materials on the accuracy of the stone die produced
    Ho W, Lin Seow L, Musawi A
    J Clin Transl Res, 2018 May 28;4(1):70-74.
    PMID: 30873496
    Background: The purpose of the present study was to investigate the effect of different viscosities of polyvinyl siloxane (PVS) impression materials on the accuracy of the stone die produced.

    Methods: A three-unit bridge master model was fabricated using cold-cure acrylic resin. Four combinations of different viscosities of PVS impression materials - regular body (monophase) alone, light body with regular body, light body with heavy body, and light body with putty - were used to make an impression of the master model. Ten impressions from each group were taken and Type IV gypsum stone was used to generate the dies. The dies were measured at the inter-abutment distance, occlusogingival length, and shoulder width with a measuring microscope and were compared with the master model using one-way analysis of variance and Tukey (honest significant difference) test.

    Results: Differences were found for inter-abutment distance between the master model and the light body with regular body and light body with putty dies (both P < 0.02). A difference was found for shoulder width between the master model and the regular body alone die (P = 0.01). No differences were found for occlusogingival distance (all P > 0.08).

    Conclusion: Results suggested inter-abutment distance was most accurate when using a PVS light body combination. Occlusogingival length was accurate using any of the studied PVS combinations, and shoulder width was more accurate when using the regular body PVS.

    Relevance for patients: These results should be considered when choosing the viscosity of the PVS to use for producing impressions of high accuracy and fabricating a well-fitting fixed prosthesis.

    Matched MeSH terms: Viscosity
  8. Valorization of Technical Lignin for the Production of Desirable Resins with High Substitution Rate and Controllable Viscosity
    Pang B, Lam SS, Shen XJ, Cao XF, Liu SJ, Yuan TQ, et al.
    ChemSusChem, 2020 Sep 07;13(17):4446-4454.
    PMID: 32118355 DOI: 10.1002/cssc.202000299
    The valorization of lignin to replace phenol is significant in the production of phenolic resins. However, a great challenge is to produce lignin-based resin (LR) with a suitable viscosity and high substitution rate of lignin to phenol. In this study, LRs were produced using hardwood technical lignin derived from the pulping industry. Structural analysis of the LRs indicated that the unsubstituted para and ortho carbon atoms of the aromatic ring influenced the curing temperature and activation energy of the resins. The curing kinetics and thermal decomposition study implied that urea and methylene groups in cured LRs were significant factors that affected the thermal stability negatively. The prepared LRs showed desirable features if used as adhesives to make plywood. This is the first approach in which a substitution rate of up to 65 % is achieved for low-reactive-site hardwood lignin, which provides a solution to the challenge of the simultaneous realization of the high addition of lignin and the adaptive viscosity of resins.
    Matched MeSH terms: Viscosity
  9. Fulltext Utilization of Bracing Arms as Additional Reinforcement in Pultruded Glass Fiber-Reinforced Polymer Composite Cross-Arms: Creep Experimental and Numerical Analyses
    Asyraf MRM, Ishak MR, Sapuan SM, Yidris N
    Polymers (Basel), 2021 Feb 19;13(4).
    PMID: 33669491 DOI: 10.3390/polym13040620
    The application of pultruded glass fiber-reinforced polymer composites (PGFRPCs) as a replacement for conventional wooden cross-arms in transmission towers is relatively new. Although numerous studies have conducted creep tests on coupon-scale PGFRPC cross-arms, none had performed creep analyses on full-scale PGFRPC cross-arms under actual working load conditions. Thus, this work proposed to study the influence of an additional bracing system on the creep responses of PGFRPC cross-arms in a 132 kV transmission tower. The creep behaviors and responses of the main members in current and braced PGFRPC cross-arm designs were compared and evaluated in a transmission tower under actual working conditions. These PGFRPC cross-arms were subjected to actual working loads mimicking the actual weight of electrical cables and insulators for a duration of 1000 h. The cross-arms were installed on a custom test rig in an open area to simulate the actual environment of tropical climate conditions. Further creep analysis was performed by using Findley and Burger models on the basis of experimental data to link instantaneous and extended (transient and viscoelastic) creep strains. The addition of braced arms to the structure reduced the total strain of a cross-arm's main member beams and improved elastic and viscous moduli. The addition of bracing arms improved the structural integrity and stiffness of the cross-arm structure. The findings of this study suggested that the use of a bracing system in cross-arm structures could prolong the structures' service life and subsequently reduce maintenance effort and cost for long-term applications in transmission towers.
    Matched MeSH terms: Viscosity
  10. Fulltext Utilisation of palm – based and beeswax coating on the postharvest-life of guava (Psidium guajava L.) during ambient and chilled storage
    Ruzaina, I., Norizzah, A.R., Halimahton Zahrah, M.S., Cheow, C.S., Adi, M.S., Noorakmar, A.W., et al.
    International Food Research Journal, 2013;20(1):265-274.
    MyJurnal
    Guava is a climacteric fruit which has high nutritional content. It is a highly perishable fruit, undergoes rapid postharvest ripening in a few days under ambient condition. This paper aims to determine the effect of palm stearin and palm kernel olein blends on maintaining the quality of guava during storage. Two different coating formulations of palm stearin (PS) and palm kernel olein (PKOo) blends (1:1 and 3:2) were analysed for their slip melting point (SMP), cohesiveness, viscosity and density. Beeswax was used as a commercial coating for comparison whiles the uncoated guava was used as control. These coatings were applied onto guavas by hand-wipe technique using a sponge. Guavas were dried in corrugated fibre board boxes and stored in an air-conditioned room maintained at 20°C while a chiller maintained at 10°C was used for chilled temperature. Coating pick up, thickness and surface area were measured while guava properties were analysed for coating effect on weight loss, O2 and CO2 gases, firmness and glossiness during storage at ambient temperature (20°C) for 21 days and chilled temperature (10ºC) for 30 days. Microstructure analysis was conducted within 2 days of coating at ambient temperature (20ºC). The results obtained indicated that 1:1 PSPKOo blends had higher cohesiveness compared to beeswax. Both PSPKOo blends significantly (p
    Matched MeSH terms: Viscosity
  11. Fulltext Unraveling the cytotoxicity and metabolic pathways of binary natural deep eutectic solvent systems
    Mbous YP, Hayyan M, Wong WF, Looi CY, Hashim MA
    Sci Rep, 2017 02 01;7:41257.
    PMID: 28145498 DOI: 10.1038/srep41257
    In this study, the anticancer potential and cytotoxicity of natural deep eutectic solvents (NADESs) were assessed using HelaS3, PC3, A375, AGS, MCF-7, and WRL-68 hepatic cell lines. NADESs were prepared from choline chloride, fructose, or glucose and compared with an N,N-diethyl ethanolammonium chloride:triethylene glycol DES. The NADESs (98 ≤ EC50 ≥ 516 mM) were less toxic than the DES (34 ≤ EC50 ≥ 120 mM). The EC50 values of the NADESs were significantly higher than those of the aqueous solutions of their individual components but were similar to those of the aqueous solutions of combinations of their chief elements. Due to the uniqueness of these results, the possibility that NADESs could be synthesized intracellularly to counterbalance the cytotoxicity of their excess principal constituents must be entertained. However, further research is needed to explore this avenue. NADESs exerted cytotoxicity by increasing membrane porosity and redox stress. In vivo, they were more destructive than the DES and induced liver failure. The potential of these mixtures was evidenced by their anticancer activity and intracellular processing. This infers that they can serve as tools for increasing our understanding of cell physiology and metabolism. It is likely that we only have begun to comprehend the nature of NADESs.
    Matched MeSH terms: Viscosity
  12. Fulltext Unexpected acceleration of Ultrasonic-Assisted iodide dosimetry in the catalytic presence of ionic liquids
    Krishnan S, Abd Ghani N, Aminuddin NF, Quraishi KS, Razafindramangarafara BL, Baup S, et al.
    Ultrason Sonochem, 2021 Jun;74:105576.
    PMID: 33975186 DOI: 10.1016/j.ultsonch.2021.105576
    This study investigates the potential of using small amounts of ionic liquids (IL) to enhance ultrasound-assisted extraction of lipids content from green microalgae. Three imidazolium-based ILs (butyl, octyl and dodecyl), each of them with two anions (bromide and acetate) were tested as additives. Viscosity and surface tension of the ILs aqueous mixtures were analyzed to determine the influence of ILs' anions and alkyl chain length, whereas KI dosimetry experiments were used as an indicator of radicals formation. A key finding suggests that the small addition of ILs improves the ultrasonication either by enhancing the viscosity and reducing the water surface tension, leading to a more powerful acoustic cavitation process or by increasing HO° production likely to oxidize the microalgae cells membranes, and consequently disrupting them on a more efficient manner. KI dosimetry also revealed that long ILs alkyl chain is detrimental. This experimental observation is confirmed thus strengthened as the yield of extracted lipids from green microalgae has shown an incremental trend when the IL concentration also increased. These hypotheses are currently under investigation to spot detailed impact of ILs on cavitation process.
    Matched MeSH terms: Viscosity
  13. Unconfined compression properties of a porous poly(vinyl alcohol)-chitosan-based hydrogel after hydration
    Lee SY, Pereira BP, Yusof N, Selvaratnam L, Yu Z, Abbas AA, et al.
    Acta Biomater, 2009 Jul;5(6):1919-25.
    PMID: 19289306 DOI: 10.1016/j.actbio.2009.02.014
    A poly(vinyl alcohol) (PVA) hydrogel composite scaffold containing N,O-carboxymethylated chitosan (NOCC) was tested to assess its potential as a scaffold for cartilage tissue engineering in a weight-bearing environment. The mechanical properties under unconfined compression for different hydration periods were investigated. The effect of supplementing PVA with NOCC (20wt.% PVA:5vol.% NOCC) produced a porosity of 43.3% and this was compared against a non-porous PVA hydrogel (20g PVA: 100ml of water, control). Under non-hydrated conditions, the porous PVA-NOCC hydrogel behaved in a similar way to the control non-porous PVA hydrogel, with similar non-linear stress-strain response under unconfined compression (0-30% strain). After 7days' hydration, the porous hydrogel demonstrated a reduced stiffness (0.002kPa, at 25% strain), resulting in a more linear stiffness relationship over a range of 0-30% strain. Poisson's ratio for the hydrated non-porous and porous hydrogels ranged between 0.73 and 1.18, and 0.76 and 1.33, respectively, suggesting a greater fluid flow when loaded. The stress relaxation function for the porous hydrogel was affected by the hydration period (from 0 to 600s); however the percentage stress relaxation regained by about 95%, after 1200s for all hydration periods assessed. No significant differences were found between the different hydration periods between the porous hydrogels and control. The calculated aggregate modulus, H(A), for the porous hydrogel reduced drastically from 10.99kPa in its non-hydrated state to about 0.001kPa after 7days' hydration, with the calculated shear modulus reducing from 30.92 to 0.14kPa, respectively. The porous PVA-NOCC hydrogel conformed to a biphasic, viscoelastic model, which has the desired properties required for any scaffold in cartilage tissue engineering.
    Matched MeSH terms: Viscosity
  14. Ultrasound-assisted weak-acid hydrolysis of crystalline starch nanoparticles for chemical enhanced oil recovery
    Agi A, Junin R, Arsad A, Abbas A, Gbadamosi A, Azli NB, et al.
    Int J Biol Macromol, 2020 Apr 01;148:1251-1271.
    PMID: 31760018 DOI: 10.1016/j.ijbiomac.2019.10.099
    Ascorbic acid was used for the first time to synthesize crystalline starch nanoparticles (CSNP). The physical properties of the CSNP were investigated. Rheological properties of the crystalline starch nanofluid (CSNF) were compared with native cassava starch (CS) and commercial polymer xanthan. Interfacial properties of the CSNF at the interface of oil and water (O/W) were investigated at different concentrations and temperatures. Wettability alteration efficiency of CSNF on oil-wet sandstone surface was investigated using the sessile drop method. Core flooding experiment was conducted at reservoir conditions. The methods were effective in producing spherical and polygonal nanoparticles with a mean diameter of 100 nm and increased in crystallinity of 7%. Viscosity increased with increase in surface area and temperature of the CSNF compared to a decrease in viscosity as the temperature increases for xanthan. Interfacial tension (IFT) decreased with increase in concentration of CSNF, electrolyte and temperature. The results show that CSNF can change the wettability of sandstone at low concentration, high salinity and elevated temperature. Pressure drops data shows stability of CSNF at 120 °C. The formation of oil bank was enough to increase oil recovery by 23%.
    Matched MeSH terms: Viscosity
  15. Fulltext Turbulence Model Selection for Low Reynolds Number Flows
    Aftab SM, Mohd Rafie AS, Razak NA, Ahmad KA
    PLoS One, 2016;11(4):e0153755.
    PMID: 27104354 DOI: 10.1371/journal.pone.0153755
    One of the major flow phenomena associated with low Reynolds number flow is the formation of separation bubbles on an airfoil's surface. NACA4415 airfoil is commonly used in wind turbines and UAV applications. The stall characteristics are gradual compared to thin airfoils. The primary criterion set for this work is the capture of laminar separation bubble. Flow is simulated for a Reynolds number of 120,000. The numerical analysis carried out shows the advantages and disadvantages of a few turbulence models. The turbulence models tested were: one equation Spallart Allmars (S-A), two equation SST K-ω, three equation Intermittency (γ) SST, k-kl-ω and finally, the four equation transition γ-Reθ SST. However, the variation in flow physics differs between these turbulence models. Procedure to establish the accuracy of the simulation, in accord with previous experimental results, has been discussed in detail.
    Matched MeSH terms: Viscosity
  16. Fulltext Treatment Of Waste Engine Oil Using Optimized Acid/Clay Refining Method
    Fathin Nadhirah Binti Kamal Ariffin, Yusilawati Ahmad Nor, Sarina Sulaiman, Nur Ayuni Jamal
    Biological and Natural Resources Engineering Journal, 2019;2(2):37-48.
    MyJurnal
    This paper addresses the treatment of waste engine oils (WEO) by acid/clay refining method using glacial acetic acid. An optimization of the process parameters in terms of settling time, stirring speed and mixing temperature for treating the WEO was performed using Response Surface Methodology to improve the quality of treated lubricating oil. The quality of the treated WEO (Castrol brand) was evaluated in terms of viscosity index and flash point value. The treated fuel quality is found to have about 95% similarity to the fresh oil used as a standard at the settling time of 24 hours, temperature of 50 °C and mixing speed of 150 rpm. Analysis of variances (ANOVA) showed that settling time plays the most significant parameters of the process followed by the mixing temperature. Solid contaminants which were collected after the treatment were analyzed using SEM-EDS. They contained rough heteregenous shaped particles with elements such as carbon (97%), calcium (1.12%), zinc (0.74%), sulphur (0.73%) and phosphorus (0.29%). Then, four different brands of WEO (Liqui Moly, Castrol, Shell and Pennzoil) were treated at the optimized conditions to determine the feasibility of the method to treat any brands of WEO. It can be concluded that the optimized treatement method is suitable to treat most of WEO. The findings of this study provide the information on the best process condition for treating WEO as well as the solid contaminants present in it.
    Matched MeSH terms: Viscosity
  17. Transesterification reaction for synthesis of palm-based ethylhexyl ester and formulation as base oil for synthetic drilling fluid
    Abdul Habib NS, Yunus R, Rashid U, Taufiq-Yap YH, Abidin ZZ, Syam AM, et al.
    J Oleo Sci, 2014;63(5):497-506.
    PMID: 24717547
    The use of vegetable oil-based ester as a base fluid in synthetic drilling fluid has become a trend in drilling operations due to its environmental advantages. The transesterification reaction of palm oil methyl ester (POME) with 2-ethylhexanol (2EH) produced 98% of palm oil-based ethylhexyl ester in less than 30 minutes. Since the transesterification reaction of POME with 2EH is a reversible reaction, its kinetics was studied in the presence of excess EH and under vacuum. The POME-to-EH molar ratio and vacuum pressure were held constant at 1:2 and 1.5 mbar respectively and the effects of temperature (70 to 110°C) were investigated. Using excess of EH and continual withdrawal of methanol via vacuum promoted the reaction to complete in less than 10 minutes. The rate constant of the reaction (k) obtained from the kinetics study was in the range of 0.44 to 0.66 s⁻¹ and the activation energy was 15.6 kJ.mol⁻¹. The preliminary investigations on the lubrication properties of drilling mud formulated with palm oil-based 2EH ester indicated that the base oil has a great potential to substitute the synthetic ester-based oil for drilling fluid. Its high kinematic viscosity provides better lubrication to the drilling fluid compared to other ester-based oils. The pour point (-15°C) and flash point (204°C) values are superior for the drilling fluid formulation. The plastic viscosity, HPHT filtrate loss and emulsion stability of the drilling fluid had given acceptable values, while gel strength and yield point could be improved by blending it with proper additives.
    Matched MeSH terms: Viscosity
  18. Fulltext Thin film flow in MHD third grade fluid on a vertical belt with temperature dependent viscosity
    Gul T, Islam S, Shah RA, Khan I, Shafie S
    PLoS One, 2014;9(6):e97552.
    PMID: 24949988 DOI: 10.1371/journal.pone.0097552
    In this work, we have carried out the influence of temperature dependent viscosity on thin film flow of a magnetohydrodynamic (MHD) third grade fluid past a vertical belt. The governing coupled non-linear differential equations with appropriate boundary conditions are solved analytically by using Adomian Decomposition Method (ADM). In order to make comparison, the governing problem has also been solved by using Optimal Homotopy Asymptotic Method (OHAM). The physical characteristics of the problem have been well discussed in graphs for several parameter of interest.
    Matched MeSH terms: Viscosity*
  19. Thermosonication and optimization of stingless bee honey processing
    Chong KY, Chin NL, Yusof YA
    Food Sci Technol Int, 2017 Oct;23(7):608-622.
    PMID: 28614964 DOI: 10.1177/1082013217713331
    The effects of thermosonication on the quality of a stingless bee honey, the Kelulut, were studied using processing temperature from 45 to 90 ℃ and processing time from 30 to 120 minutes. Physicochemical properties including water activity, moisture content, color intensity, viscosity, hydroxymethylfurfural content, total phenolic content, and radical scavenging activity were determined. Thermosonication reduced the water activity and moisture content by 7.9% and 16.6%, respectively, compared to 3.5% and 6.9% for conventional heating. For thermosonicated honey, color intensity increased by 68.2%, viscosity increased by 275.0%, total phenolic content increased by 58.1%, and radical scavenging activity increased by 63.0% when compared to its raw form. The increase of hydroxymethylfurfural to 62.46 mg/kg was still within the limits of international standards. Optimized thermosonication conditions using response surface methodology were predicted at 90 ℃ for 111 minutes. Thermosonication was revealed as an effective alternative technique for honey processing.
    Matched MeSH terms: Viscosity
  20. The use of inter-conversion equations on bituminous binder data
    NUR IZZI MD.YUSOFF, MOHD ROSLI HAININ, MOUNIER D, AIREY GD
    Sains Malaysiana, 2013;42:1647-1654.
    According to the classical theory of viscoelasticity, a linear viscoelastic (LVE) function can be converted into another viscoelastic function even though they emphasize different information. In this study, dynamic tests were conducted on different conventional penetration grade bitumens using a dynamic shear rheometer (DSR) in the LVE region. The results showed that the dynamic data in the frequency domain can be converted into the time domain functions using a numerical technique. This was done with the aid of the non-linear regularization (NLREG) computer program. The NLREG software is a computer program for solving nonlinear ill-posed problem and is based on non-linear Tikhonov regularization method. The use of data interconversion equation is found suitable for converting from the frequency domain into the time domain of conventional penetration grade bitumens.
    Matched MeSH terms: Viscosity
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