Displaying publications 1 - 20 of 81 in total

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  1. A DNA biosensor based on gold nanoparticle decorated on carboxylated multi-walled carbon nanotubes for gender determination of Arowana fish
    Saeedfar K, Heng LY, Chiang CP
    Bioelectrochemistry, 2017 Dec;118:106-113.
    PMID: 28780443 DOI: 10.1016/j.bioelechem.2017.07.012
    Multi-wall carbon nanotubes (MWCNTs) were modified to design a new DNA biosensor. Functionalized MWCNTs were equipped with gold nanoparticles (GNPs) (~15nm) (GNP-MWCNTCOOH) to construct DNA biosensors based on carbon-paste screen-printed (SPE) electrodes. GNP attachment onto functionalized MWCNTs was carried out by microwave irradiation and was confirmed by spectroscopic studies and surface analysis. DNA biosensors based on differential pulse voltammetry (DPV) were constructed by immobilizing thiolated single-stranded DNA probes onto GNP-MWCNTCOOH. Ruthenium (III) chloride hexaammoniate [Ru(NH3)6,2Cl(-)] (RuHex) was used as hybridization redox indicator. RuHex and MWCNT interaction was low in compared to other organic redox hybridization indicators. The linear response range for DNA determination was 1×10(-21) to 1×10(-9)M with a lower detection limit of 1.55×10(-21)M. Thus, the attachment of GNPs onto functionalized MWCNTs yielded sensitive DNA biosensor with low detection limit and stability more than 30days. Constructed electrode was used to determine gender of arowana fish.
    Matched MeSH terms: Sonication
  2. A new approach of probe sonication assisted ionic liquid conversion of glucose, cellulose and biomass into 5-hydroxymethylfurfural
    Sarwono A, Man Z, Muhammad N, Khan AS, Hamzah WSW, Rahim AHA, et al.
    Ultrason Sonochem, 2017 Jul;37:310-319.
    PMID: 28427638 DOI: 10.1016/j.ultsonch.2017.01.028
    5-Hydroxymethylfurfural (HMF) has been identified as a promising biomass-derived platform chemical. In this study, one pot production of HMF was studied in ionic liquid (IL) under probe sonication technique. Compared with the conventional heating technique, the use of probe ultrasonic irradiation reduced the reaction time from hours to minutes. Glucose, cellulose and local bamboo, treated with ultrasonic, produced HMF in the yields of 43%, 31% and 13% respectively, within less than 10min. The influence of various parameters such as acoustic power, reaction time, catalysts and glucose loading were studied. About 40% HMF yield at glucose conversion above 90% could be obtained with 2% of catalyst in 3min. Negligible amount of soluble by-product was detected, and humin formation could be controlled by adjusting the different process parameters. Upon extraction of HMF, the mixture of ionic liquid and catalyst could be reused and exhibited no significant reduction of HMF yield over five successive runs. The purity of regenerated [C4C1im]Cl and HMF was confirmed by NMR spectroscopy, indicating neither changes in the chemical structure nor presence of any major contaminants during the conversion under ultrasonic treatment. 13C NMR suggests that [C4C1im]Cl/CrCl3 catalyses mutarotation of α-glucopyranose to β-glucopyranose leading to isomerization and finally conversion to HMF. The experimental results demonstrate that the use of probe sonication technique for conversion to HMF provides a positive process benefit.
    Matched MeSH terms: Sonication*
  3. A review on the formation of titania nanotube photocatalysts by hydrothermal treatment
    Wong CL, Tan YN, Mohamed AR
    J Environ Manage, 2011 Jul;92(7):1669-80.
    PMID: 21450395 DOI: 10.1016/j.jenvman.2011.03.006
    Titania nanotubes are gaining prominence in photocatalysis, owing to their excellent physical and chemical properties such as high surface area, excellent photocatalytic activity, and widespread availability. They are easily produced by a simple and effective hydrothermal method under mild temperature and pressure conditions. This paper reviews and analyzes the mechanism of titania nanotube formation by hydrothermal treatment. It further examines the parameters that affect the formation of titania nanotubes, such as starting material, sonication pretreatment, hydrothermal temperature, washing process, and calcination process. Finally, the effects of the presence of dopants on the formation of titania nanotubes are analyzed.
    Matched MeSH terms: Sonication
  4. A technique for evaluating the oil/heavy-oil viscosity changes under ultrasound in a simulated porous medium
    Hamidi H, Mohammadian E, Junin R, Rafati R, Manan M, Azdarpour A, et al.
    Ultrasonics, 2014 Feb;54(2):655-62.
    PMID: 24075416 DOI: 10.1016/j.ultras.2013.09.006
    Theoretically, Ultrasound method is an economical and environmentally friendly or "green" technology, which has been of interest for more than six decades for the purpose of enhancement of oil/heavy-oil production. However, in spite of many studies, questions about the effective mechanisms causing increase in oil recovery still existed. In addition, the majority of the mechanisms mentioned in the previous studies are theoretical or speculative. One of the changes that could be recognized in the fluid properties is viscosity reduction due to radiation of ultrasound waves. In this study, a technique was developed to investigate directly the effect of ultrasonic waves (different frequencies of 25, 40, 68 kHz and powers of 100, 250, 500 W) on viscosity changes of three types of oil (Paraffin oil, Synthetic oil, and Kerosene) and a Brine sample. The viscosity calculations in the smooth capillary tube were based on the mathematical models developed from the Poiseuille's equation. The experiments were carried out for uncontrolled and controlled temperature conditions. It was observed that the viscosity of all the liquids was decreased under ultrasound in all the experiments. This reduction was more significant for uncontrolled temperature condition cases. However, the reduction in viscosity under ultrasound was higher for lighter liquids compare to heavier ones. Pressure difference was diminished by decreasing in the fluid viscosity in all the cases which increases fluid flow ability, which in turn aids to higher oil recovery in enhanced oil recovery (EOR) operations. Higher ultrasound power showed higher liquid viscosity reduction in all the cases. Higher ultrasound frequency revealed higher and lower viscosity reduction for uncontrolled and controlled temperature condition experiments, respectively. In other words, the reduction in viscosity was inversely proportional to increasing the frequency in temperature controlled experiments. It was concluded that cavitation, heat generation, and viscosity reduction are three of the promising mechanisms causing increase in oil recovery under ultrasound.
    Matched MeSH terms: Sonication/methods*
  5. Fulltext Application of ultrasonication at different microbial growth stages during apple juice fermentation by Lactobacillus plantarum: Investigation on the metabolic response
    Wang H, Tao Y, Li Y, Wu S, Li D, Liu X, et al.
    Ultrason Sonochem, 2021 May;73:105486.
    PMID: 33639530 DOI: 10.1016/j.ultsonch.2021.105486
    In this work, low-intensity ultrasonication (58.3 and 93.6 W/L) was performed at lag, logarithmic and stationary growth phases of Lactobacillus plantarum in apple juice fermentation, separately. Microbial responses to sonication, including microbial growth, profiles of organic acids profile, amino acids, phenolics, and antioxidant capacity, were examined. The results revealed that obvious responses were made by Lactobacillus plantarum to ultrasonication at lag and logarithmic phases, whereas sonication at stationary phase had a negligible impact. Sonication at lag and logarithmic phases promoted microbial growth and intensified biotransformation of malic acid to lactic acid. For example, after sonication at lag phase for 0.5 h, microbial count and lactic acid content in the ultrasound-treated samples at 58.3 W/L reached 7.91 ± 0.01 Log CFU/mL and 133.70 ± 7.39 mg/L, which were significantly higher than that in the non-sonicated samples. However, the ultrasonic effect on microbial growth and metabolism of organic acids attenuated with fermentation. Moreover, ultrasonication at lag and logarithmic phases had complex influences on the metabolism of apple phenolics such as chlorogenic acid, caffeic acid, procyanidin B2, catechin and gallic acid. Ultrasound could positively affect the hydrolysis of chlorogenic acid to caffeic acid, the transformation of procyanidin B2 and decarboxylation of gallic acid. The metabolism of organic acids and free amino acids in the sonicated samples was statistically correlated with phenolic metabolism, implying that ultrasound may benefit phenolic derivation by improving the microbial metabolism of organic acids and amino acids.
    Matched MeSH terms: Sonication/methods*
  6. Fulltext Binary solvent extraction system and extraction time effects on phenolic antioxidants from kenaf seeds (Hibiscus cannabinus L.) extracted by a pulsed ultrasonic-assisted extraction
    Wong YH, Lau HW, Tan CP, Long K, Nyam KL
    ScientificWorldJournal, 2014;2014:789346.
    PMID: 24592184 DOI: 10.1155/2014/789346
    The aim of this study was to determine the best parameter for extracting phenolic-enriched kenaf (Hibiscus cannabinus L.) seeds by a pulsed ultrasonic-assisted extraction. The antioxidant activities of ultrasonic-assisted kenaf seed extracts (KSE) were determined by a 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity assay, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging assay, β -carotene bleaching inhibition assay, and ferric reducing antioxidant power (FRAP) assay. Total phenolic content (TPC) and total flavonoid content (TFC) evaluations were carried out to determine the phenolic and flavonoid contents in KSE. The KSE from the best extraction parameter was then subjected to high performance liquid chromatography (HPLC) to quantify the phenolic compounds. The optimised extraction condition employed 80% ethanol for 15 min, with the highest values determined for the DPPH, ABTS, and FRAP assay. KSE contained mainly tannic acid (2302.20 mg/100 g extract) and sinapic acid (1198.22 mg/100 g extract), which can be used as alternative antioxidants in the food industry.
    Matched MeSH terms: Sonication/methods*
  7. Biorefinery of Chlorella sorokiniana using ultra sonication assisted liquid triphasic flotation system
    Koyande AK, Chew KW, Lim JW, Lam MK, Ho YC, Show PL
    Bioresour Technol, 2020 May;303:122931.
    PMID: 32044648 DOI: 10.1016/j.biortech.2020.122931
    The aim of this work was to study the ultrasonication-assisted Liquid Tri-phasic Flotation (LTF) System to obtain lipid and protein from microalgae Chlorella sorokiniana in a single step as a novel process. In the current study, biorefinery of Chlorella sorokiniana was performed using LTF system in a single step. The highest protein recovery of 97.43 ± 1.67% and lipid recovery of 69.50 ± 0.54% were obtained. The corresponding parameters were microalgae biomass loading of 0.5 w/v%, ammonium sulphate concentration of 40 w/v%, volume ratio of 1:1.5 (salt:alcohol), ultrasonication pulse mode of 20 s ON/20 s OFF at 20% amplitude for 5 mins, flotation air flowrate of 100 mL/min. Additionally, recycling of alcohol phase to study the circular nature of proposed biorefinery was investigated. The proposed LTF system for extraction of proteins and lipid reduces the number of operation units required in this biorefinery approach.
    Matched MeSH terms: Sonication
  8. Fulltext Characterization and in vivo study of decellularized aortic scaffolds using closed sonication system
    Hazwani A, Sha'Ban M, Azhim A
    Organogenesis, 2019;15(4):120-136.
    PMID: 31495272 DOI: 10.1080/15476278.2019.1656997
    Extracellular matrix (ECM) based bioscaffolds prepared by decellularization has increasingly emerged in tissue engineering application because it has structural, biochemical, and biomechanical cues that have dramatic effects upon cell behaviors. Therefore, we developed a closed sonication decellularization system to prepare ideal bioscaffolds with minimal adverse effects on the ECM. The decellularization was achieved at 170 kHz of ultrasound frequency in 0.1% and 2% Sodium Dodecyl Sulphate (SDS) solution for 10 hours. The immersion treatment as control was performed to compare the decellularization efficiency with our system. Cell removal and ECM structure were determined by histological staining and biochemical assay. Biomechanical properties were investigated by the indentation testing to test the stiffness, a residual force and compression of bioscaffolds. Additionally, in vivo implantation was performed in rat to investigate host tissue response. Compared to native tissues, histological staining and biochemical assay confirm the absence of cellularity with preservation of ECM structure. Moreover, sonication treatment has not affected the stiffness [N/mm] and a residual force [N] of the aortic scaffolds except for compression [%] which 2% SDS significantly decreased compared to native tissues showing higher SDS has a detrimental effect on ECM structure. Finally, minimal inflammatory response was observed after 1 and 5 weeks of implantation. This study reported that the novelty of our developed closed sonication system to prepare ideal bioscaffolds for tissue engineering applications.
    Matched MeSH terms: Sonication*
  9. Chitosan/halloysite beads fabricated by ultrasonic-assisted extrusion-dripping and a case study application for copper ion removal
    Choo CK, Kong XY, Goh TL, Ngoh GC, Horri BA, Salamatinia B
    Carbohydr Polym, 2016 Mar 15;138:16-26.
    PMID: 26794733 DOI: 10.1016/j.carbpol.2015.11.060
    Development of new materials for different applications especially as bio-composites has received great attention. This study concentrates on development of a biopolymer based on chitosan (CT) and halloysite nanotubes (HNT) and evaluates the copper removal intake as a potential application of this bio-composite. In this study, CT/HNT beads were prepared by ultrasonic-assisted extrusion-dripping method for the first time. Two sources of HNTs (i.e. Dragonite and Matauri Bay) were added into a chitosan solution (2wt.%) at various loading fractions (25, 50, 75wt.%). The effect of ultrasound as a mixing device was also studied by varying the amplitude at constant frequency of 25%, 50% and 75%. Characteristics and physical properties of the prepared CT/HNT beads were also analyzed by SEM, FTIR, TGA and BET the results show that introducing HNT to chitosan increases the adsorption capacity toward copper ions; however HNT loading fraction above 50wt.% resulted in a decrease in adsorption capacity attributed to limited accessibility of the amino groups. The adsorption capacity of the CT/HNT beads prepared from Dragonite source had a larger adsorption capacity of 14.2mg/g as compared to that of Matauri Bay, 10.55mg/g. It was observed that the adsorption capacity of the beads toward copper ions decreased when the loading fraction of HNT is increased at constant ultrasound amplitude. The result of this study helps to understand the links between the characteristics and adsorption abilities of CT/HNT beads.
    Matched MeSH terms: Sonication
  10. Comparative study on the process behavior and reaction kinetics in sonocatalytic degradation of organic dyes by powder and nanotubes TiO2
    Pang YL, Abdullah AZ
    Ultrason Sonochem, 2012 May;19(3):642-51.
    PMID: 22000097 DOI: 10.1016/j.ultsonch.2011.09.007
    Sonocatalytic degradation of various organic dyes (Congo Red, Reactive Blue 4, Methyl Orange, Rhodamine B and Methylene Blue) catalyzed by powder and nanotubes TiO(2) was studied. Both catalysts were characterized using transmission electron microscope (TEM), surface analyzer, Raman spectroscope and thermal gravimetric analyzer (TGA). Sonocatalytic activity of powder and nanotubes TiO(2) was elucidated based on the degradation of various organic dyes. The former catalyst was favorable for treatment of anionic dyes, while the latter was more beneficial for cationic dyes. Sonocatalytic activity of TiO(2) nanotubes could be up to four times as compared to TiO(2) powder under an ultrasonic power of 100 W and a frequency of 42 kHz. This was associated with the higher surface area and the electrostatic attraction between dye molecules and TiO(2) nanotubes. Fourier transform-infrared spectrometer (FT-IR) was used to identify changes that occurred on the functional group in Rhodamine B molecules and TiO(2) nanotubes after the reaction. Sonocatalytic degradation of Rhodamine B by TiO(2) nanotubes apparently followed the Langmuir-Hinshelwood adsorption kinetic model with surface reaction rate of 1.75 mg/L min. TiO(2) nanotubes were proven for their high potential to be applied in sonocatalytic degradation of organic dyes.
    Matched MeSH terms: Sonication/methods*
  11. Fulltext Development of decellularized meniscus using closed sonication treatment system: potential scaffolds for orthopedics tissue engineering applications
    Yusof F, Sha'ban M, Azhim A
    Int J Nanomedicine, 2019;14:5491-5502.
    PMID: 31410000 DOI: 10.2147/IJN.S207270
    PURPOSE: Meniscus is a fibrocartilagenous tissue that cannot effectively heal due to its complex structure and presence of avascular zone. Thus, tissue engineering and regenerative medicine offer an alternative for the regeneration of meniscus tissues using bioscaffolds as a replacement for the damaged one. The aim of this study was to prepare an ideal meniscus bioscaffold with minimal adverse effect on extracellular matrix components (ECMs) using a sonication treatment system.

    METHODS: The decellularization was achieved using a developed closed sonication treatment system for 10 hrs, and continued with a washing process for 5 days. For the control, a simple immersion treatment was set as a benchmark to compare the decellularization efficiency. Histological and biochemical assays were conducted to investigate the cell removal and retention of the vital extracellular matrix. Surface ultrastructure of the prepared scaffolds was evaluated using scanning electron microscope at 5,000× magnification viewed from cross and longitudinal sections. In addition, the biomechanical properties were investigated through ball indentation testing to study the stiffness, residual forces and compression characteristics. Statistical significance between the samples was determined with p-value =0.05.

    RESULTS: Histological and biochemical assays confirmed the elimination of antigenic cellular components with the retention of the vital extracellular matrix within the sonicated scaffolds. However, there was a significant removal of sulfated glycosaminoglycans. The surface histoarchitecture portrayed the preserved collagen fibril orientation and arrangement. However, there were minor disruptions on the structure, with few empty micropores formed which represented cell lacunae. The biomechanical properties of bioscaffolds showed the retention of viscoelastic behavior of the scaffolds which mimic native tissues. After immersion treatment, those scaffolds had poor results compared to the sonicated scaffolds due to the inefficiency of the treatment.

    CONCLUSION: In conclusion, this study reported that the closed sonication treatment system had high capabilities to prepare ideal bioscaffolds with excellent removal of cellular components, and retained extracellular matrix and biomechanical properties.

    Matched MeSH terms: Sonication/methods*
  12. Effect of duration of sonication during gelatinization on properties of tapioca starch water hyacinth fiber biocomposite
    Asrofi M, Abral H, Putra YK, Sapuan SM, Kim HJ
    Int J Biol Macromol, 2018 Mar;108:167-176.
    PMID: 29191420 DOI: 10.1016/j.ijbiomac.2017.11.165
    This paper characterizes properties of biocomposite sonicated during gelatinization. The biocomposite consisted of tapioca starch based plastic reinforced by 10% volume fraction of water hyacinth fiber (WHF). During gelatinization, the biocomposite was poured into a rectangular glass mold then vibrated in an ultrasonic bath using 40kHz, 250W for varying durations (0, 15, 30, and 60min). The resulting biocomposite was then dried in a drying oven at 50°C for 20h. The results of this study indicate that a biocomposite with optimal properties can be produced using tapioca starch and WHF if the gelatinizing mixture is exposed to ultrasound vibration for 30min. After this vibration duration, tensile strength (TS) and tensile modulus (TM) increased 83% and 108%. A further 60min vibration only increased the TS at 13% and TM at 23%. Moisture resistance of the biocomposite after vibration increased by around 25% reaching a maximal level after 30min. Thermal resistance of the vibrated biocomposites was also increased.
    Matched MeSH terms: Sonication*
  13. Effect of low Fe3+ doping on characteristics, sonocatalytic activity and reusability of TiO2 nanotubes catalysts for removal of Rhodamine B from water
    Pang YL, Abdullah AZ
    J Hazard Mater, 2012 Oct 15;235-236:326-35.
    PMID: 22939090 DOI: 10.1016/j.jhazmat.2012.08.008
    Fe-doped titanium dioxide (TiO(2)) nanotubes were prepared using sol-gel followed by hydrothermal methods and characterized using various methods. The sonocatalytic activity was evaluated based on oxidation of Rhodamine B under ultrasonic irradiation. Iron ions (Fe(3+)) might incorporate into the lattice and intercalated in the interlayer spaces of TiO(2) nanotubes. The catalysts showed narrower band gap energies, higher specific surface areas, more active surface oxygen vacancies and significantly improved sonocatalytic activity. The optimum Fe doping at Fe:Ti=0.005 showed the highest sonocatalytic activity and exceeded that of un-doped TiO(2) nanotubes by a factor of 2.3 times. It was believed that Fe(3+) doping induced the formation of new states close to the valence band and conduction bands and accelerated the separation of charge carriers. Leached Fe(3+) could catalyze Fenton-like reaction and led to an increase in the hydroxyl radical (OH) generation. Fe-doped TiO(2) nanotubes could retain high degradation efficiency even after being reused for 4 cycles with minimal loss of Fe from the surface of the catalyst.
    Matched MeSH terms: Sonication
  14. Effect of ultrasound on the growth of probiotics and bioconversion of isoflavones in prebiotic-supplemented soymilk
    Yeo SK, Liong MT
    J Agric Food Chem, 2011 Feb 9;59(3):885-97.
    PMID: 21235273 DOI: 10.1021/jf103974d
    The objective of the present study was to evaluate the effects of ultrasound on the growth of probiotics and bioconversion of isoflavones in prebiotic-soymilk. Previous studies have shown that ultrasound elevated microbial enzymatic activity and growth by altering cellular membranes. The growth of probiotics was significantly decreased (P < 0.05) immediately after ultrasound treatment, attributed to membrane permeabilization, cell lysis, and membrane lipid peroxidation upon ultrasound treatment. The ultrasound treatment also caused alteration at the acyl chain, polar head, and interface region of the probiotic membrane phospholipid bilayers. The cells treated with ultrasound showed recovery from injury with subsequent increase in growth upon fermentation in soymilk (P < 0.05). Ultrasound treatment at 100 W for 2 and 3 min also enhanced (P < 0.05) the intracellular and extracellular β-glucosidase activity of probiotics, leading to increased (P < 0.05) bioconversion of glucosides to aglycones in the prebiotic-soymilk. Our present study illustrated that ultrasound treatment could produce bioactive synbiotic-soymilk with increased concentrations of bioactive aglycones.
    Matched MeSH terms: Sonication*
  15. Fulltext Effects of Accelerated Weathering on Degradation Behavior of Basalt Fiber Reinforced Polymer Nanocomposites
    Hashim UR, Jumahat A, Jawaid M, Dungani R, Alamery S
    Polymers (Basel), 2020 Nov 06;12(11).
    PMID: 33172162 DOI: 10.3390/polym12112621
    This work aims to give insight on the effect of accelerated weathering, i.e., the combination of ultraviolet (UV) exposure and water spraying, on the visual and mechanical properties of basalt fiber reinforced polymer (BFRP) composites. The solvent exchange method, sonication and high shear milling technique were used to prepare the nanocomposite laminates. Three types of laminates were fabricated, i.e., unmodified BFRP, nanosilica modified BFRP and graphene nanoplatelet (GNP) modified BFRP composites with the total fiber loading of 45 wt.%. Glass fiber reinforced polymer (GFRP) laminate was also prepared for performance comparison purposes between the natural and synthetic fibers. The laminates were exposed to UV with a total weathering condition of 504 h using a Quantum-UV accelerated weathering tester. The weathering condition cycle was set at 8 h 60 °C UV exposure and 4 h 50 °C condensation. The discoloration visual inspection on the tested specimen was observed under the optical microscope. The obtained results showed that the UV exposure and water absorption caused severe discoloration of the laminates due to photo-oxidation reaction. The effect of weathering conditions on tensile and flexural properties of unmodified BFRP composites indicated that the UV exposure and water absorption caused reduction by 12% in tensile strength and by 7% in flexural strength. It is also found that the reduction in tensile and flexural properties of nanomodified BFRP composites was smaller than the unmodified system. It concluded from this work, that the mineral based composites (i.e., BFRP) has high potential for structural applications owing to its better properties than synthetic based composites (i.e., GFRP).
    Matched MeSH terms: Sonication
  16. Fulltext Effects of Sonication and Thermal Pasteurization on the Nutritional, Antioxidant, and Microbial Properties of Noni Juice
    Choo YX, Teh LK, Tan CX
    Molecules, 2022 Dec 30;28(1).
    PMID: 36615507 DOI: 10.3390/molecules28010313
    Sonication is recognized as a potential food processing method to improve the functional properties of fruit juice. This study evaluated the effects of different sonication durations (20, 40, and 60 min) and thermal pasteurization on the nutritional, antioxidant, and microbial properties of noni juice. Fresh noni juice served as the control. The main organic acids detected were malic (57.54−89.31 mg/100 mL) and ascorbic (17.15−31.55 mg/100 mL) acids. Compared with the fresh sample, the concentrations of these compounds were significantly improved (p < 0.05) in the 60 min sonicated sample but reduced (p < 0.05) in the pasteurized sample. Moreover, sonication for 60 min resulted in increments of scopoletin, rutin, and vanillic acid compared to the fresh sample. The antioxidant activity of the juice sample was improved in the sample sonicated for 60 min. Irrespective of juice processing method, the level of microbial counts in noni juice was within the satisfactory level over the 8 weeks of refrigerated (4 °C) storage. This study highlights the feasibility of using ultrasound processing to enhance the quality of noni juice on the industrial scale.
    Matched MeSH terms: Sonication
  17. Effects of thermal treatment and sonication on quality attributes of Chokanan mango (Mangifera indica L.) juice
    Santhirasegaram V, Razali Z, Somasundram C
    Ultrason Sonochem, 2013 Sep;20(5):1276-82.
    PMID: 23538119 DOI: 10.1016/j.ultsonch.2013.02.005
    Ultrasonic treatment is an emerging food processing technology that has growing interest among health-conscious consumers. Freshly squeezed Chokanan mango juice was thermally treated (at 90 °C for 30 and 60s) and sonicated (for 15, 30 and 60 min at 25 °C, 40 kHz frequency, 130 W) to compare the effect on microbial inactivation, physicochemical properties, antioxidant activities and other quality parameters. After sonication and thermal treatment, no significant changes occurred in pH, total soluble solids and titratable acidity. Sonication for 15 and 30 min showed significant improvement in selected quality parameters except color and ascorbic acid content, when compared to freshly squeezed juice (control). A significant increase in extractability of carotenoids (4-9%) and polyphenols (30-35%) was observed for juice subjected to ultrasonic treatment for 15 and 30 min, when compared to the control. In addition, enhancement of radical scavenging activity and reducing power was observed in all sonicated juice samples regardless of treatment time. Thermal and ultrasonic treatment exhibited significant reduction in microbial count of the juice. The results obtained support the use of sonication to improve the quality of Chokanan mango juice along with safety standard as an alternative to thermal treatment.
    Matched MeSH terms: Sonication*
  18. Fulltext Effects of thermosonication on the fate of Escherichia coli O157:H7 and Salmonella Enteritidis in mango juice
    Kiang WS, Bhat R, Rosma A, Cheng LH
    Lett Appl Microbiol, 2013 Apr;56(4):251-7.
    PMID: 23278854 DOI: 10.1111/lam.12042
    In this study, the effects of thermosonication and thermal treatment on Escherichia coli O157:H7 and Salmonella Enteritidis in mango juice were investigated at 50 and 60°C. Besides, nonlethal injury of Salm. Enteritidis after both treatments was also examined. The highest inactivation was attained with thermosonication at 60°C. The inactivation rate was different for both pathogens, and Salm. Enteritidis was found to be more sensitive to thermosonication than E. coli O157:H7. Salmonella Enteritidis was recovered in all treated samples, except those subjected to more than 5-min thermosonication at 60°C. It was found that the introduction of high-intensity ultrasound enhanced the inactivation of pathogens compared to thermal treatment alone. On the other hand, Salm. Enteritidis was detected in a number of samples following incubation in universal pre-enrichment broth, but no growth was detected after incubation in mango juice.
    Matched MeSH terms: Sonication*
  19. Fulltext Elucidation of Antimicrobial Activity of Non-Covalently Dispersed Carbon Nanotubes
    Saleemi MA, Fouladi MH, Yong PVC, Wong EH
    Materials (Basel), 2020 Apr 03;13(7):6-6.
    PMID: 32260216 MyJurnal DOI: 10.3390/ma13071676
    Microorganisms have begun to develop resistance because of inappropriate and extensive use of antibiotics in the hospital setting. Therefore, it seems to be necessary to find a way to tackle these pathogens by developing new and effective antimicrobial agents. Carbon nanotubes (CNTs) have attracted growing attention because of their remarkable mechanical strength, electrical properties, and chemical and thermal stability for their potential applications in the field of biomedical as therapeutic and diagnostic nanotools. However, the impact of carbon nanotubes on microbial growth has not been fully investigated. The primary purpose of this research study is to investigate the antimicrobial activity of CNTs, particularly double-walled and multi-walled nanotubes on representative pathogenic strains such as Gram-positive bacteria Staphylococcus aureus, Gram-negative bacteria Pseudomonas aeruginosa, Klebsiella pneumoniae, and fungal strain Candida albicans. The dispersion ability of CNT types (double-walled and multi-walled) treated with a surfactant such as sodium dodecyl-benzenesulfonate (SDBS) and their impact on the microbial growth inhibition were also examined. A stock concentration 0.2 mg/mL of both double-walled and multi-walled CNTs was prepared homogenized by dispersing in surfactant solution by using probe sonication. UV-vis absorbance, Fourier transform infrared spectroscopy (FTIR), and transmission electron microscopy (TEM) were used for the characterization of CNTs dispersed in the surfactant solution to study the interaction between molecules of surfactant and CNTs. Later, scanning electron microscopy (SEM) was used to investigate how CNTs interact with the microbial cells. The antimicrobial activity was determined by analyzing optical density growth curves and viable cell count. This study revealed that microbial growth inhibited by non-covalently dispersed CNTs was both depend on the concentration and treatment time. In conclusion, the binding of surfactant molecules to the surface of CNTs increases its ability to disperse in aqueous solution. Non-covalent method of CNTs dispersion preserved their structure and increased microbial growth inhibition as a result. Multi-walled CNTs exhibited higher antimicrobial activity compared to double-walled CNTs against selected pathogens.
    Matched MeSH terms: Sonication
  20. Fulltext Enhanced Thermal and Dynamic Mechanical Properties of Synthetic/Natural Hybrid Composites with Graphene Nanoplateletes
    Jesuarockiam N, Jawaid M, Zainudin ES, Thariq Hameed Sultan M, Yahaya R
    Polymers (Basel), 2019 Jun 26;11(7).
    PMID: 31247898 DOI: 10.3390/polym11071085
    The aim of the present research work is to enhance the thermal and dynamic mechanical properties of Kevlar/Cocos nucifera sheath (CS)/epoxy composites with graphene nano platelets (GNP). Laminates were fabricated through the hand lay-up method followed by hot pressing. GNP at different wt.% (0.25, 0.5, and 0.75) were incorporated with epoxy resin through ultra-sonication. Kevlar/CS composites with different weight ratios (100/0, 75/25, 50/50, 25/75, 0/100) were fabricated while maintaining a fiber/matrix weight ratio at 45/55. Thermal degradation and viscoelastic properties were evaluated using thermogravimetric analysys (TGA), differential scanning calorimetric (DSC) analysis, and a dynamic mechanical analyser (DMA). The obtained results revealed that Kevlar/CS (25/75) hybrid composites at 0.75 wt.% of GNP exhibited similar thermal stability compared to Kevlar/epoxy (100/0) composites at 0 wt.% of GNP. It has been corroborated with DSC observation that GNP act as a thermal barrier. However, DMA results showed that the Kevlar/CS (50/50) hybrid composites at 0.75 wt.% of GNP exhibited almost equal viscoelastic properties compared to Kevlar/epoxy (100/0) composites at 0 wt.% GNP due to effective crosslinking, which improves the stress transfer rate. Hence, this research proved that Kevlar can be efficiently (50%) replaced with CS at an optimal GNP loading for structural applications.
    Matched MeSH terms: Sonication
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