Displaying publications 141 - 160 of 307 in total

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  1. Fulltext Impact of optimised cooking on the antioxidant activity in edible mushrooms
    Ng ZX, Tan WC
    J Food Sci Technol, 2017 Nov;54(12):4100-4111.
    PMID: 29085153 DOI: 10.1007/s13197-017-2885-0
    This study aimed to investigate the effect of four cooking methods with different durations on the in vitro antioxidant activities of five edible mushrooms, namely Agaricus bisporus, Flammulina velutipes, Lentinula edodes, Pleurotus ostreatus and Pleurotus eryngii. Among the raw samples, A. bisporus showed the highest total antioxidant activity (reducing power and radical scavenging), total flavonoid, ascorbic acid and water soluble phenolic contents. Short-duration steam cooking (3 min) increased the total flavonoid and ascorbic acid while prolonged pressure cooking (15 min) reduced the water soluble phenolic content in the mushrooms. The retention of antioxidant value in the mushrooms varied with the variety of mushroom after the cooking process. The cooking duration significantly affected the ascorbic acid in the mushrooms regardless of cooking method. To achieve the best antioxidant values, steam cooking was preferred for F. velutipes (1.5 min), P. ostreatus (4.5 min) and L. edodes (4.5 min) while microwave cooking for 1.5 min was a better choice for A. bisporus. Pressure cooked P. eryngii showed the best overall antioxidant value among the cooked samples. Optimised cooking method including pressure cooking could increase the antioxidant values in the edible mushrooms.
    Matched MeSH terms: Microwaves
  2. Microwave induced plasma for solid fuels and waste processing: A review on affecting factors and performance criteria
    Ho GS, Faizal HM, Ani FN
    Waste Manag, 2017 Nov;69:423-430.
    PMID: 28811144 DOI: 10.1016/j.wasman.2017.08.015
    High temperature thermal plasma has a major drawback which consumes high energy. Therefore, non-thermal plasma which uses comparatively lower energy, for instance, microwave plasma is more attractive to be applied in gasification process. Microwave-induced plasma gasification also carries the advantages in terms of simplicity, compactness, lightweight, uniform heating and the ability to operate under atmospheric pressure that gains attention from researchers. The present paper synthesizes the current knowledge available for microwave plasma gasification on solid fuels and waste, specifically on affecting parameters and their performance. The review starts with a brief outline on microwave plasma setup in general, and followed by the effect of various operating parameters on resulting output. Operating parameters including fuel characteristics, fuel injection position, microwave power, addition of steam, oxygen/fuel ratio and plasma working gas flow rate are discussed along with several performance criteria such as resulting syngas composition, efficiency, carbon conversion, and hydrogen production rate. Based on the present review, fuel retention time is found to be the key parameter that influences the gasification performance. Therefore, emphasis on retention time is necessary in order to improve the performance of microwave plasma gasification of solid fuels and wastes.
    Matched MeSH terms: Microwaves*
  3. One-pot microwave assisted stereoselective synthesis of novel dihydro-2'H-spiro[indene-2,1'-pyrrolo-[3,4-c]pyrrole]-tetraones and evaluation of their antimycobacterial activity and inhibition of AChE
    Bharkavi C, Vivek Kumar S, Ashraf Ali M, Osman H, Muthusubramanian S, Perumal S
    Bioorg Med Chem Lett, 2017 Jul 15;27(14):3071-3075.
    PMID: 28552337 DOI: 10.1016/j.bmcl.2017.05.050
    An efficient one-pot microwave assisted stereoselective synthesis of novel dihydro-2'H-spiro[indene-2,1'-pyrrolo[3,4-c]pyrrole]-tetraone derivatives through three-component 1,3-dipolar cycloaddition of azomethine ylides generated in situ from ninhydrin and sarcosine with a series of 1-aryl-1H-pyrrole-2,5-diones is described. The synthesised compounds were screened for their antimycobacterial and AChE inhibition activities. Compound 4b (IC50 1.30µM) has been found to display twelve fold antimycobacterial activity compared to cycloserine and it is thirty seven times more active than pyrimethamine. Compound 4h displays maximum AchE inhibitory activity with IC50 value of 0.78±0.01µmol/L.
    Matched MeSH terms: Microwaves*
  4. Fulltext Enhanced Handover Decision Algorithm in Heterogeneous Wireless Network
    Abdullah RM, Zukarnain ZA
    Sensors (Basel), 2017 Jul 14;17(7).
    PMID: 28708067 DOI: 10.3390/s17071626
    Transferring a huge amount of data between different network locations over the network links depends on the network's traffic capacity and data rate. Traditionally, a mobile device may be moved to achieve the operations of vertical handover, considering only one criterion, that is the Received Signal Strength (RSS). The use of a single criterion may cause service interruption, an unbalanced network load and an inefficient vertical handover. In this paper, we propose an enhanced vertical handover decision algorithm based on multiple criteria in the heterogeneous wireless network. The algorithm consists of three technology interfaces: Long-Term Evolution (LTE), Worldwide interoperability for Microwave Access (WiMAX) and Wireless Local Area Network (WLAN). It also employs three types of vertical handover decision algorithms: equal priority, mobile priority and network priority. The simulation results illustrate that the three types of decision algorithms outperform the traditional network decision algorithm in terms of handover number probability and the handover failure probability. In addition, it is noticed that the network priority handover decision algorithm produces better results compared to the equal priority and the mobile priority handover decision algorithm. Finally, the simulation results are validated by the analytical model.
    Matched MeSH terms: Microwaves
  5. Fulltext A Printed Xi-Shaped Left-Handed Metamaterial on Low-Cost Flexible Photo Paper
    Ashraf FB, Alam T, Islam MT
    Materials (Basel), 2017 Jul 05;10(7).
    PMID: 28773113 DOI: 10.3390/ma10070752
    A Xi-shaped meta structure, has been introduced in this paper. A modified split-ring resonator (MSRR) and a capacitive loaded strip (CLS) were used to achieve the left-handed property of the metamaterial. The structure was printed using silver metallic nanoparticle ink, using a very low-cost photo paper as a substrate material. Resonators were inkjet-printed using silver nanoparticle metallic ink on paper to make this metamaterial flexible. It is also free from any kind of chemical waste, which makes it eco-friendly. A double negative region from 8.72 GHz to 10.91 GHz (bandwidth of 2.19 GHz) in the X-band microwave spectra was been found. Figure of merit was also obtained to measure any loss in the double negative region. The simulated result was verified by the performance of the fabricated prototype. The total dimensions of the proposed structure were 0.29 λ × 0.29 λ × 0.007 λ. It is a promising unit cell because of its simplicity, cost-effectiveness, and easy fabrication process.
    Matched MeSH terms: Microwaves
  6. Pyrolysis of corn stalk biomass briquettes in a scaled-up microwave technology
    Salema AA, Afzal MT, Bennamoun L
    Bioresour Technol, 2017 Jun;233:353-362.
    PMID: 28285228 DOI: 10.1016/j.biortech.2017.02.113
    Pyrolysis of corn stalk biomass briquettes was carried out in a developed microwave (MW) reactor supplied with 2.45GHz frequency using 3kW power generator. MW power and biomass loading were the key parameters investigated in this study. Highest bio-oil, biochar, and gas yield of 19.6%, 41.1%, and 54.0% was achieved at different process condition. In terms of quality, biochar exhibited good heating value (32MJ/kg) than bio-oil (2.47MJ/kg). Bio-oil was also characterised chemically using FTIR and GC-MS method. This work may open new dimension towards development of large-scale MW pyrolysis technology.
    Matched MeSH terms: Microwaves
  7. Extraction of bioactives from Orthosiphon stamineus using microwave and ultrasound-assisted techniques: Process optimization and scale up
    Chan CH, See TY, Yusoff R, Ngoh GC, Kow KW
    Food Chem, 2017 Apr 15;221:1382-1387.
    PMID: 27979103 DOI: 10.1016/j.foodchem.2016.11.016
    This work demonstrated the optimization and scale up of microwave-assisted extraction (MAE) and ultrasonic-assisted extraction (UAE) of bioactive compounds from Orthosiphon stamineus using energy-based parameters such as absorbed power density and absorbed energy density (APD-AED) and response surface methodology (RSM). The intensive optimum conditions of MAE obtained at 80% EtOH, 50mL/g, APD of 0.35W/mL, AED of 250J/mL can be used to determine the optimum conditions of the scale-dependent parameters i.e. microwave power and treatment time at various extraction scales (100-300mL solvent loading). The yields of the up scaled conditions were consistent with less than 8% discrepancy and they were about 91-98% of the Soxhlet extraction yield. By adapting APD-AED method in the case of UAE, the intensive optimum conditions of the extraction, i.e. 70% EtOH, 30mL/g, APD of 0.22W/mL, AED of 450J/mL are able to achieve similar scale up results.
    Matched MeSH terms: Microwaves/therapeutic use*
  8. A combined microwave pretreatment/solvent extraction process for the production of oil from palm fruit: optimisation, oil quality and effect of prolonged exposure
    Tan JC, Chuah CH, Cheng SF
    J Sci Food Agric, 2017 Apr;97(6):1784-1789.
    PMID: 27470073 DOI: 10.1002/jsfa.7975
    BACKGROUND: Conventional palm oil milling involves multiple stages after fruit collection; in particular, oil clarification introduces water into the pressed oil, which results in a large quantity of wastewater.

    RESULTS: A combined process of microwave pretreatment and solvent extraction to mill crude palm oil, without introducing water or steam, is described. An excellent yield (up to 30%) of oil was obtained with pretreatment in a 42 L, 1000 W and 2450 MHz microwave oven followed by hexane extraction. The optimum conditions (10 min microwave pretreatment and 12 h solvent extraction) yielded an oil with a low free fatty acid content (<1.0%) and an acceptable anisidine value (<3.0 meq kg(-1) ). The oil had a fatty acid composition not resembling those of conventional crude palm oil and crude palm kernel oil. In the pretreatment, the leached oil had 6.3% lauric acid whereas the solvent extracted oil had only 1.5% lauric acid. Among the factors affecting the oil quality, microwave pretreatment affected the oil quality significantly; however, an optimised duration that would ensure high efficiency in solvent extraction also resulted in ruptured fruitlets, although not to the extent of causing excessive oxidation. In fact, microwave pretreatment should exceed 12 min; after only 15 min, the oil had 1-methylcyclopentanol (12.96%), 1-tetradecanol (9.44%), 1-nonadecene (7.22%), nonanal (7.13%) and 1-tridecene (5.09%), which probably arose from the degradation of fibres.

    CONCLUSION: Microwave pretreatment represents an alternative milling process for crude palm oil compared with conventional processes in the omission of wet treatment with steam. © 2016 Society of Chemical Industry.

    Matched MeSH terms: Microwaves
  9. Fulltext Green Microwave-Assisted Combustion Synthesis of Zinc Oxide Nanoparticles with Citrullus colocynthis (L.) Schrad: Characterization and Biomedical Applications
    Azizi S, Mohamad R, Mahdavi Shahri M
    Molecules, 2017 Feb 16;22(2).
    PMID: 28212344 DOI: 10.3390/molecules22020301
    In this paper, a green microwave-assisted combustion approach to synthesize ZnO-NPs using zinc nitrate and Citrullus colocynthis (L.) Schrad (fruit, seed and pulp) extracts as bio-fuels is reported. The structure, optical, and colloidal properties of the synthesized ZnO-NP samples were studied. Results illustrate that the morphology and particle size of the ZnO samples are different and depend on the bio-fuel. The XRD results revealed that hexagonal wurtzite ZnO-NPs with mean particle size of 27-85 nm were produced by different bio-fuels. The optical band gap was increased from 3.25 to 3.40 eV with the decreasing of particle size. FTIR results showed some differences in the surface structures of the as-synthesized ZnO-NP samples. This led to differences in the zeta potential, hydrodynamic size, and more significantly, antioxidant activity through scavenging of 1, 1-Diphenyl-2-picrylhydrazyl (DPPH) free radicals. In in vitro cytotoxicity studies on 3T3 cells, a dose dependent toxicity with non-toxic effect of concentration below 0.26 mg/mL was shown for ZnO-NP samples. Furthermore, the as-synthesized ZnO-NPs inhibited the growth of medically significant pathogenic gram-positive (Bacillus subtilis and Methicillin-resistant Staphylococcus aurous) and gram-negative (Peseudomonas aeruginosa and Escherichia coli) bacteria. This study provides a simple, green and efficient approach to produce ZnO nanoparticles for various applications.
    Matched MeSH terms: Microwaves*
  10. Microwave as skin permeation enhancer for transdermal drug delivery of chitosan-5-fluorouracil nanoparticles
    Nawaz A, Wong TW
    Carbohydr Polym, 2017 Feb 10;157:906-919.
    PMID: 27988008 DOI: 10.1016/j.carbpol.2016.09.080
    This study investigated transdermal drug delivery mechanisms of chitosan nanoparticles with the synergistic action of microwave in skin modification. Chitosan nanoparticles, with free or conjugated 5-fluorouracil, were prepared by nanospray-drying technique. Their transdermal drug delivery profiles across untreated and microwave-treated skins (2450MHz 5min, 5+5min; 3985MHz 5min) were examined. Both constituent materials of nanoparticles and drug encapsulation were required to succeed transdermal drug delivery. The drug transport was mediated via nanoparticles carrying drug across the skin and/or diffusion of earlier released drug molecules from skin surfaces. The drug/nanoparticles transport was facilitated through constituent nanoparticles and microwave fluidizing protein/lipid domains of epidermis and dermis (OH, NH, CH, CN) and dermal trans-to-gauche lipid conformational changes. The microwave induced marked changes to the skin ceramide content homogeneity. The chitosan nanoparticles largely affected the palmitic acid and keratin domains. Combined microwave and nanotechnologies synergize transdermal drug delivery.
    Matched MeSH terms: Microwaves*
  11. Microwaved bacterial cellulose-based hydrogel microparticles for the healing of partial thickness burn wounds
    Pandey M, Mohamad N, Low WL, Martin C, Mohd Amin MC
    Drug Deliv Transl Res, 2017 02;7(1):89-99.
    PMID: 27815776 DOI: 10.1007/s13346-016-0341-8
    Burn wound management is a complex process because the damage may extend as far as the dermis which has an acknowledged slow rate of regeneration. This study investigates the feasibility of using hydrogel microparticles composed of bacterial cellulose and polyacrylamide as a dressing material for coverage of partial-thickness burn wounds. The microparticulate carrier structure and surface morphology were investigated by Fourier transform infrared, X-ray diffraction, elemental analysis, and scanning electron microscopy. The cytotoxicity profile of the microparticles showed cytocompatibility with L929 cells. Dermal irritation test demonstrated that the hydrogel was non-irritant to the skin and had a significant effect on wound contraction compared to the untreated group. Moreover, histological examination of in vivo burn healing samples revealed that the hydrogel treatment enhanced epithelialization and accelerated fibroblast proliferation with wound repair and intact skin achieved by the end of the study. Both the in vitro and in vivo results proved the biocompatibility and efficacy of hydrogel microparticles as a wound dressing material.
    Matched MeSH terms: Microwaves*
  12. N-doped TiO2 synthesised via microwave induced photocatalytic on RR4 dye removal under LED light irradiation
    Azami MS, Nawawi WI, Ali H. Jawad, Ishak MAM, Azami MS, K. Ismail
    Sains Malaysiana, 2017;46:1390-1316.
    Nitrogen doped titanium dioxide (N-doped TiO2
    ) was synthesized by microwave using urea as nitrogen sources with
    commercially available TiO2
    -P25. The N-doped TiO2
    was compared with unmodified TiO2
    by carrying out the investigation
    on its properties using x-ray diffraction (XRD) analysis, Brunauer-Emmett-Teller (BET), Fourier transformed infrared
    spectroscopy (FTIR) and diffuse reflectance spectroscopy (UV-Vis DRS). The photocatalytic activities of N-doped TiO2
    and unmodified TiO2 were studied for photodegradation of reactive red 4 (RR4) under light emitting diode (LED) light
    irradiation. An active photoresponse under LED light irradiation was observed from N-doped TiO2
    with 60 min of time
    irradiation to complete RR4 color removal while no photocatalytic degradation was observed from unmodified.
    Matched MeSH terms: Microwaves
  13. Fulltext Effect of microwave-assisted extraction on the yield and quality of apple pomace and lemon peel pectins
    Zarei, M., Ahmadi Zenouz, A., Saari, N., Ghanbari, R., Nikkhah, M., Vaziri, M.
    International Food Research Journal, 2017;24(6):2402-2407.
    MyJurnal
    Microwave assisted extraction treatments showed the higher pectin yields of 10.07% and 8.83% in pretreated samples by microwave and 9.4% and 8% in the extraction of dried after microwave treatment in lemon peel and apple pomace samples, respectively. Lemon peel pectin in pretreated samples by microwave and extraction of dried after microwave treatment showed the higher degree of esterification 71.8% and 70%, respectively, while apple pomace revealed 68% and 65.4% in same treatments. Furthermore, lemon peel pectin exhibited the highest galacturonic content of 74.5% in extraction of pretreated samples by microwave, while apple pomace pectin indicated the higher galacturonic acid content of 70.5% and 70% in both extraction of dried after microwave treatment and extraction of dried samples. Texture analysis of jellies prepared by various extracted pectin indicated the highest fracturability in the microwave-assisted drying treatment of 33 N and 32.5 N for apple pomace and lemon peel pectin, respectively.
    Matched MeSH terms: Microwaves
  14. Fulltext A microwave low noise amplifier for long term evolution (LTE) application
    Abu Bakar Ibrahim, Ashardi Abas
    Journal of Engineering and Science Research, 2017;1(2):203-208.
    MyJurnal
    Wireless communication is a technology that plays an important role in current technology transformation. wireless communication is a method of telecommunication that are available for transmitting large amounts of data, voice and video over long distance using different frequencies. Specifically, Low Noise Amplifier which is located at the first block of receiver system, makes it one of the important element in improving signal transmission. This study was aimed to design a microwave Low Noise Amplifier for Long Term Evolution (LTE) application that will work at 5.8 GHz using high-performance low noise superHEMT transistor FHX76LP manufactured by Eudyna Technologies. The low noise amplifier (LNA) produced gain of 17.2 dB and noise figure (NF) of 0.914 dB. The input reflection (S11) and output return loss (S22) are -17.8 dB and -19.6 dB respectively. The bandwidth of the amplifier recorded is 1.2 GHz. The input sensitivity is compliant with the Long Term Evolution (LTE) standards.
    Matched MeSH terms: Microwaves
  15. The influence of microwave cooking on the nutritional composition and antioxidant activity of the underutilized perah seed
    Li KS, Ali A, Muhammad II
    Acta Sci Pol Technol Aliment, 2017 Jul-Sep;16(3):283-292.
    PMID: 29055976 DOI: 10.17306/J.AFS.0497
    BACKGROUND: Perah seed is one of the most underutilized oilseeds, containing high nutritional values and high percentage of α-linoleneic acid, which may have a high potential in food and pharmaceutical applica- tions. The main objective of this study was to evaluate the influence of microwave (MW) cooking on the proximate composition and antioxidant activity of perah seeds.

    METHODS: In this study, the proximate composition and amygdalin concentration of MW ir- radiated perah seeds were determined. The total phenolic content (TPC), Maillard reaction products (MRPs) and antioxidant activity of methanol (PME), 70% methanol in water (PMW), ethanol (PEE), 70% ethanol  in water (PEW) extracts and methanol extract of oil (PMO) were evaluated during MW cooking. The anti- oxidant activity was evaluated using multiple assays, namely DPPH radical scavenging activity, β-Carotene bleaching assay, and reducing power.

    RESULTS: Microwave cooking did not significantly increase crude lipid and carbohydrate content, and the amounts of other nutrients such as ash, crude protein and fibre remained almost unchanged. As evaluated  by HPLC, the amygdalin concentration in the seeds was reduced by MW cooking. The TPC, MRP and anti- oxidant activity of the solvent extracts of perah seeds increased significantly with increasing roasting time. Of all the extracts, PMW at all MW cooking times displayed the highest antioxidant effectiveness. However, thermal treatment significantly reduced the antioxidant properties of PMO. The values for TPC, MRP and antioxidant effectiveness of the samples were ranked in the following order: PMW > PEW > PME > PEE > PMO, in both control and microwaved samples.

    CONCLUSIONS: In determining the overall quality of the products, MW cooking time was found to be a critical factor. Solubilization of phenolic compounds and formation of MRPs during MW cooking could have caused the increase in antioxidant activity of the perah seeds.
    Matched MeSH terms: Microwaves*
  16. Fulltext Microwave bio-sensor based on symmetrical split ring resonator with spurline filters for therapeutic goods detection
    Alahnomi RA, Zakaria Z, Ruslan E, Ab Rashid SR, Mohd Bahar AA, Shaaban A
    PLoS One, 2017;12(9):e0185122.
    PMID: 28934301 DOI: 10.1371/journal.pone.0185122
    A novel symmetrical split ring resonator (SSRR) based microwave sensor with spurline filters for detecting and characterizing the properties of solid materials has been developed. Due to the weak perturbation in the interaction of material under test (MUT) and planar microwave sensor, spurline filters were embedded to the SSRR microwave sensor which effectively enhanced Q-factor with suppressing the undesired harmonic frequency. The spurline filter structures force the presented sensor to resonate at a fundamental frequency of 2.2 GHz with the capabilities of suppressing rejected harmonic frequency and miniaturization in circuit size. A wide bandwidth rejection is achieved by using double spurlines filters with high Q-factor achievement (up to 652.94) compared to single spurline filter. The new SSRR sensor with spurline filters displayed desired properties such as high sensitivity, accuracy, and performance with a 1.3% typical percentage error in the measurement results. Furthermore, the sensor has been successfully applied for detecting and characterizing solid materials (such as Roger 5880, Roger 4350, and FR4) and evidently demonstrated that it can suppress the harmonic frequency effectively. This novel design with harmonic suppression is useful for various applications such as food industry (meat, fruit, vegetables), biological medicine (derived from proteins and other substances produced by the body), and Therapeutic goods (antiseptics, vitamins, anti-psychotics, and other medicines).
    Matched MeSH terms: Microwaves*
  17. Fulltext Electromagnetic Performances Analysis of an Ultra-wideband and Flexible Material Antenna in Microwave Breast Imaging: To Implement A Wearable Medical Bra
    Rahman A, Islam MT, Singh MJ, Kibria S, Akhtaruzzaman M
    Sci Rep, 2016 12 23;6:38906.
    PMID: 28008923 DOI: 10.1038/srep38906
    In this paper, we report a compact and ultra-wide band antenna on a flexible substrate using the 5-(4-(perfluorohexyl)phenyl)thiophene-2-carbaldehyde compound for microwave imaging. In contrast to other microwave based imaging systems, such as an array of 16 antennas, we proposed a bi-static radar based imaging system consisting of two omnidirectional antennas, which reduces complexity and the overall dimension. The proposed compact antennas are 20 × 14 mm2 and designed for operating at frequencies from 4 to 6 GHz. To allow for implantation into a bra, the electromagnetic performances of the antennas must be considered in bending conditions. In comparison with the recently reported flexible antennas, we demonstrated both electromagnetic performance and imaging reconstruction for bending conditions. For the proof of concept, the electromagnetic performances both at flat and bending conditions have been verified using a homogeneous multilayer model of the human breast phantom. Our results demonstrate that the antenna, even at bending conditions, exhibits an excellent omni-directional radiation pattern with an average efficiency above 70% and average gain above 1 dBi, within the operational frequency band. The comprehensive aim of the realized antenna is to design a biodegradable and wearable antenna-based bra for early breast cancer detection in the future.
    Matched MeSH terms: Microwaves*
  18. Sequential ultrasound-microwave assisted acid extraction (UMAE) of pectin from pomelo peels
    Liew SQ, Ngoh GC, Yusoff R, Teoh WH
    Int J Biol Macromol, 2016 Dec;93(Pt A):426-435.
    PMID: 27565298 DOI: 10.1016/j.ijbiomac.2016.08.065
    This study aims to optimize sequential ultrasound-microwave assisted extraction (UMAE) on pomelo peel using citric acid. The effects of pH, sonication time, microwave power and irradiation time on the yield and the degree of esterification (DE) of pectin were investigated. Under optimized conditions of pH 1.80, 27.52min sonication followed by 6.40min microwave irradiation at 643.44W, the yield and the DE value of pectin obtained was respectively at 38.00% and 56.88%. Based upon optimized UMAE condition, the pectin from microwave-ultrasound assisted extraction (MUAE), ultrasound assisted extraction (UAE) and microwave assisted extraction (MAE) were studied. The yield of pectin adopting the UMAE was higher than all other techniques in the order of UMAE>MUAE>MAE>UAE. The pectin's galacturonic acid content obtained from combined extraction technique is higher than that obtained from sole extraction technique and the pectin gel produced from various techniques exhibited a pseudoplastic behaviour. The morphological structures of pectin extracted from MUAE and MAE closely resemble each other. The extracted pectin from UMAE with smaller and more regular surface differs greatly from that of UAE. This has substantiated the highest pectin yield of 36.33% from UMAE and further signified their compatibility and potentiality in pectin extraction.
    Matched MeSH terms: Microwaves*
  19. Fulltext A simple design for microwave assisted digestion vessel with low reagent consumption suitable for food and environmental samples
    Gholami M, Behkami S, Zain SM, Bakirdere S
    Sci Rep, 2016 11 17;6:37186.
    PMID: 27853264 DOI: 10.1038/srep37186
    The objective of this work is to prepare a cost-effective, low reagent consumption and high performance polytetrafluoroethylene (PTFE) vessel that is capable to work in domestic microwave for digesting food and environmental samples. The designed vessel has a relatively thicker wall compared to that of commercial vessels. In this design, eight vessels are placed in an acrylonitrile butadiene styrene (ABS) holder to keep them safe and stable. This vessel needs only 2.0 mL of HNO3 and 1.0 mL H2O2 to digest 100 mg of biological sample. The performance of this design is then evaluated with an ICP-MS instrument in the analysis of the several NIST standard reference material of milk 1849a, rice flour 1568b, spinach leave 1570a and Peach Leaves 1547 in a domestic microwave oven with inverter technology. Outstanding agreement to (SRM) values are observed by using the suggested power to time microwave program, which simulates the reflux action occurring in this closed vessel. Taking into account the high cost of commercial microwave vessels and the volume of chemicals needed for various experiments (8-10 mL), this simple vessel is cost effective and suitable for digesting food and environmental samples.
    Matched MeSH terms: Microwaves
  20. Microwave-assisted extraction of polysaccharides from Cyphomandra betacea and its biological activities
    C SK, M S, K R
    Int J Biol Macromol, 2016 Nov;92:682-693.
    PMID: 27456125 DOI: 10.1016/j.ijbiomac.2016.07.062
    Response Surface Methodology (RSM) was used to optimize the parameters for microwave-assisted extraction of polysaccharides from Cyphomandra betacea. The results showed a good fit with a second-order polynomial equation that was statistically acceptable at P<0.05. Optimal conditions for the extraction of polysaccharides were: extraction time, 2h; microwave power, 400W; extraction temperature, 60°C; and ratio of raw material to water 1:40 (g/mL). Under the optimized conditions, the yield of polysaccharides was found to be relatively high (about 36.52%). The in vitro biological activities of antioxidant and antitumor were evaluated. The IC50 value of polysaccharides was found to be 3mg/mL. The percentage of Cell viability was determined by MTT assay. Our results showed that polysaccharides inhibited proliferation of MCF-7 (Breast carcinoma), A549 (Human lung carcinoma) and HepG2 (Liver carcinoma) with an IC50 of 0.23mg/mL, 0.17mg/mL and 0.62mg/mL respectively after 48h incubation. Polysaccharides were shown to promote apoptosis as seen in the nuclear morphological examination study using acridine orange (AO) and ethidium bromide (EB) staining. This is the first report on the effects of polysaccharides extracted from Cyphomandra betacea which exhibited stronger antioxidant and antitumor activities.
    Matched MeSH terms: Microwaves*
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