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Effect of heating on oxidation stability and fatty acid composition of microwave roasted groundnut seed oil

Abbas Ali M, Anowarul Islam M, Othman NH, Noor AM

J Food Sci Technol, 2017 Dec;54(13):4335-4343.
PMID: 29184239 DOI: 10.1007/s13197-017-2904-1

The oxidative stability and fatty acid composition of groundnut seed oil (GSO) exposed to microwaves were evaluated during heating at 170 °C. During heating, the oxidative indices such as free fatty acid, peroxide value, p-anisidine value, TOTOX, thiobarbituric acid value, specific extinctions, and color value were increased. The increments were found to be higher in unroasted seed oils compared to roasted ones indicating lower release of lipid oxidation products in roasted GSO. After 9 h heating, the relative content of polyunsaturated fatty acid (PUFA) decreased to 89.53% and that of saturated fatty acid (SFA) increased to 117.46% in unroasted sample. The relative content of PUFA decreased to 92.05% and that of SFA increased to 105.76% in 7.5 min roasted sample after 9 h of heating. However, the roasting process slowed down the oxidative deterioration of PUFA. With increased heating times, an appreciable loss was more apparent in the triacylglycerol species OLL and OOL in unroasted samples compared to roasted ones. In FTIR, the peak intensities in unroasted samples were markedly changed in comparison with roasted samples during heating. The roasting of groundnut seed prior to the oil extraction reduced the oxidative degradation of oil samples; thereby increasing heat stability.

Matched MeSH terms: Microwaves
Generalized Likelihood Uncertainty Estimation (GLUE) methodology for optimization of extraction in natural products

Maulidiani, Rudiyanto, Abas F, Ismail IS, Lajis NH

Food Chem, 2018 Jun 01;250:37-45.
PMID: 29412925 DOI: 10.1016/j.foodchem.2018.01.023

Optimization process is an important aspect in the natural product extractions. Herein, an alternative approach is proposed for the optimization in extraction, namely, the Generalized Likelihood Uncertainty Estimation (GLUE). The approach combines the Latin hypercube sampling, the feasible range of independent variables, the Monte Carlo simulation, and the threshold criteria of response variables. The GLUE method is tested in three different techniques including the ultrasound, the microwave, and the supercritical CO2 assisted extractions utilizing the data from previously published reports. The study found that this method can: provide more information on the combined effects of the independent variables on the response variables in the dotty plots; deal with unlimited number of independent and response variables; consider combined multiple threshold criteria, which is subjective depending on the target of the investigation for response variables; and provide a range of values with their distribution for the optimization.

Matched MeSH terms: Microwaves
Determination of biogenic amines in chicken, beef, and mutton by dansyl chloride microwave derivatization in Malaysia

Yue CS, Lim AK, Chia ML, Wong PY, Chin JSR, Wong WH

J Food Sci, 2023 Feb;88(2):650-665.
PMID: 36624628 DOI: 10.1111/1750-3841.16404

In this study, an improved dansyl-chloride derivatization technique using a microwave synthesizer was used for the qualitative and quantitative analyses of biogenic amine in the fresh meat samples. The derivatization technique was optimized in terms of temperature, reaction time, and spinning speed. The derivatization method together with a validated reversed-phase HPLC-DAD method was used for the determination of biogenic amines in chicken, beef, and mutton sold in the wet market. The results of the analyses showed that tryptamine, putrescine, and histamine were generally detected in all the three types of meat. Higher levels of histamine were found in chicken and beef. However, low levels of histamine were observed in mutton. Tyramine was either detected low or moderate in all the three types of meat. The biogenic amines of the fresh meat sold in the wet market is generally higher than the reported values. The mechanisms of biogenic amines-dansyl-chloride formation were investigated and proposed. PRACTICAL APPLICATION: The biogenic amine derivatization method was improved. The improved derivatization method can be potentially used for various food products beside meats for routine biogenic amine analyses due to its fast analysis time and simplicity. High levels of biogenic amines were generally found in the meat sold in the wet markets. However, proper handling of the raw meat can reduce the risk of infection.

Matched MeSH terms: Microwaves
Fulltext Synthesis and characterization of polylactide/rice husk hydrochar composite

Nizamuddin S, Jadhav A, Qureshi SS, Baloch HA, Siddiqui MTH, Mubarak NM, et al.

Sci Rep, 2019 Apr 01;9(1):5445.
PMID: 30931991 DOI: 10.1038/s41598-019-41960-1

Polymer composites are fabricated by incorporating fillers into a polymer matrix. The intent for addition of fillers is to improve the physical, mechanical, chemical and rheological properties of the composite. This study reports on a unique polymer composite using hydrochar, synthesised by microwave-assisted hydrothermal carbonization of rice husk, as filler in polylactide matrix. The polylactide/hydrochar composites were fabricated by incorporating hydrochar in polylactide at 5%, 10%, 15% and 20 wt% by melt processing in a Haake rheomix at 170 °C. Both the neat polylactide and polylactide/hydrochar composite were characterized for mechanical, structural, thermal and rheological properties. The tensile modulus of polylactide/hydrochar composites was improved from 2.63 GPa (neat polylactide) to 3.16 GPa, 3.33 GPa, 3.54 GPa, and 4.24 GPa after blending with hydrochar at 5%, 10%, 15%, and 20%, respectively. Further, the incorporation of hydrochar had little effect on storage modulus (G') and loss modulus (G″). The findings of this study reported that addition of hydrochar improves some characteristics of polylactide composites suggesting the potential of hydrochar as filler for polymer/hydrochar composites.

Matched MeSH terms: Microwaves
Tropical fruit wastes including durian seeds and rambutan peels as a precursor for producing activated carbon using H3PO4-assisted microwave method: RSM-BBD optimization and mechanism for methylene blue dye adsorption

Tamjid Farki NNANL, Abdulhameed AS, Surip SN, ALOthman ZA, Jawad AH

Int J Phytoremediation, 2023;25(12):1567-1578.
PMID: 36794599 DOI: 10.1080/15226514.2023.2175780

Herein, tropical fruit biomass wastes including durian seeds (DS) and rambutan peels (RP) were used as sustainable precursors for preparing activated carbon (DSRPAC) using microwave-induced H3PO4 activation. The textural and physicochemical characteristics of DSRPAC were investigated by N2 adsorption-desorption isotherms, X-ray diffraction, Fourier transform infrared, point of zero charge, and scanning electron microscope analyses. These findings reveal that the DSRPAC has a mean pore diameter of 3.79 nm and a specific surface area of 104.2 m2/g. DSRPAC was applied as a green adsorbent to extensively investigate the removal of an organic dye (methylene blue, MB) from aqueous solutions. The response surface methodology Box-Behnken design (RSM-BBD) was used to evaluate the vital adsorption characteristics, which included (A) DSRPAC dosage (0.02-0.12 g/L), (B) pH (4-10), and (C) time (10-70 min). The BBD model specified that the DSRPAC dosage (0.12 g/L), pH (10), and time (40 min) parameters caused the largest removal of MB (82.1%). The adsorption isotherm findings reveal that MB adsorption pursues the Freundlich model, whereas the kinetic data can be well described by the pseudo-first-order and pseudo-second-order models. DSRPAC exhibited good MB adsorption capability (118.5 mg/g). Several mechanisms control MB adsorption by the DSRPAC, including electrostatic forces, π-π stacking, and H-bonding. This work shows that DSRPAC derived from DS and RP could serve as a viable adsorbent for the treatment of industrial effluents containing organic dye.

Matched MeSH terms: Microwaves
Production of activated carbon from food wastes (chicken bones and rice waste) by microwave assisted ZnCl2 activation: an optimized process for crystal violet dye removal

Mohd Radhuwan SN, Abdulhameed AS, Jawad AH, ALOthman ZA, Wilson LD, Algburi S

Int J Phytoremediation, 2024;26(5):699-709.
PMID: 37740478 DOI: 10.1080/15226514.2023.2260004

A major worldwide challenge that presents significant economic, environmental, and social concerns is the rising generation of food waste. The current work used chicken bones (CB) and rice (R) food waste as alternate precursors for the production of activated carbon (CBRAC) by microwave radiation-assisted ZnCl2 activation. The adsorption characteristics of CBRAC were investigated in depth by removing an organic dye (crystal violet, CV) from an aquatic environment. To establish ideal conditions from the significant adsorption factors (A: CBRAC dosage (0.02-0.12 g/100 mL); B: pH (4-10); and C: duration (30-420), a numerical desirability function of Box-Behnken design (BBD) was utilized. The highest CV decolorization by CBRAC was reported to be 90.06% when the following conditions were met: dose = 0.118 g/100 mL, pH = 9.0, and time = 408 min. Adsorption kinetics revealed that the pseudo-first order (PFO) model best matches the data, whereas the Langmuir model was characterized by equilibrium adsorption, where the adsorption capacity of CBRAC for CV dye was calculated to be 57.9 mg/g. CV adsorption is accomplished by several processes, including electrostatic forces, pore diffusion, π-π stacking, and H-bonding. This study demonstrates the use of CB and R as biomass precursors for the efficient creation of CBRAC and their use in wastewater treatment, resulting in a greener environment.

Matched MeSH terms: Microwaves
Fulltext A Sustainable Approach to the Stereoselective Synthesis of Diazaheptacyclic Cage Systems Based on a Multicomponent Strategy in an Ionic Liquid

Suresh Kumar R, Almansour AI, Arumugam N, Altaf M, Menéndez JC, Kumar RR, et al.

Molecules, 2016 Jan 29;21(2):165.
PMID: 26840282 DOI: 10.3390/molecules21020165

The microwave-assisted three-component reactions of 3,5-bis(E)-arylmethylidene]tetrahydro-4(1H)-pyridinones, acenaphthenequinone and cyclic α-amino acids in an ionic liquid, 1-butyl-3-methylimidazolium bromide, occurred through a domino sequence affording structurally intriguing diazaheptacyclic cage-like compounds in excellent yields.

Matched MeSH terms: Microwaves
Microwave-assisted fabrication of titanium implants with controlled surface topography for rapid bone healing

Kutty MG, De A, Bhaduri SB, Yaghoubi A

ACS Appl Mater Interfaces, 2014 Aug 27;6(16):13587-93.
PMID: 25095907 DOI: 10.1021/am502967n

Morphological surface modifications have been reported to enhance the performance of biomedical implants. However, current methods of introducing graded porosity involves postprocessing techniques that lead to formation of microcracks, delamination, loss of fatigue strength, and, overall, poor mechanical properties. To address these issues, we developed a microwave sintering procedure whereby pure titanium powder can be readily densified into implants with graded porosity in a single step. Using this approach, surface topography of implants can be closely controlled to have a distinctive combination of surface area, pore size, and surface roughness. In this study, the effect of various surface topographies on in vitro response of neonatal rat calvarial osteoblast in terms of attachment and proliferation is studied. Certain graded surfaces nearly double the chance of cell viability in early stages (∼one month) and are therefore expected to improve the rate of healing. On the other hand, while the osteoblast morphology significantly differs in each sample at different periods, there is no straightforward correlation between early proliferation and quantitative surface parameters such as average roughness or surface area. This indicates that the nature of cell-surface interactions likely depends on other factors, including spatial parameters.

Matched MeSH terms: Microwaves*
Rapid detection of Ganoderma-infected oil palms by microwave ergosterol extraction with HPLC and TLC

Muniroh MS, Sariah M, Zainal Abidin MA, Lima N, Paterson RR

J Microbiol Methods, 2014 May;100:143-7.
PMID: 24681306 DOI: 10.1016/j.mimet.2014.03.005

Detection of basal stem rot (BSR) by Ganoderma of oil palms was based on foliar symptoms and production of basidiomata. Enzyme-Linked Immunosorbent Assays-Polyclonal Antibody (ELISA-PAB) and PCR have been proposed as early detection methods for the disease. These techniques are complex, time consuming and have accuracy limitations. An ergosterol method was developed which correlated well with the degree of infection in oil palms, including samples growing in plantations. However, the method was capable of being optimised. This current study was designed to develop a simpler, more rapid and efficient ergosterol method with utility in the field that involved the use of microwave extraction. The optimised procedure involved extracting a small amount of Ganoderma, or Ganoderma-infected oil palm suspended in low volumes of solvent followed by irradiation in a conventional microwave oven at 70°C and medium high power for 30s, resulting in simultaneous extraction and saponification. Ergosterol was detected by thin layer chromatography (TLC) and quantified using high performance liquid chromatography with diode array detection. The TLC method was novel and provided a simple, inexpensive method with utility in the field. The new method was particularly effective at extracting high yields of ergosterol from infected oil palm and enables rapid analysis of field samples on site, allowing infected oil palms to be treated or culled very rapidly. Some limitations of the method are discussed herein. The procedures lend themselves to controlling the disease more effectively and allowing more effective use of land currently employed to grow oil palms, thereby reducing pressure to develop new plantations.

Matched MeSH terms: Microwaves*
High yield production of sugars from deproteinated palm kernel cake under microwave irradiation via dilute sulfuric acid hydrolysis

Fan SP, Jiang LQ, Chia CH, Fang Z, Zakaria S, Chee KL

Bioresour Technol, 2014 Feb;153:69-78.
PMID: 24342947 DOI: 10.1016/j.biortech.2013.11.055

Recent years, great interest has been devoted to the conversion of biomass-derived carbohydrate into sugars, such as glucose, mannose and fructose. These are important versatile intermediate products that are easily processed into high value-added biofuels. In this work, microwave-assisted dilute sulfuric acid hydrolysis of deproteinated palm kernel cake (DPKC) was systematically studied using Response Surface Methodology. The highest mannose yield (92.11%) was achieved at the optimized condition of 148°C, 0.75N H2SO4, 10min 31s and substrate to solvent (SS) ratio (w/v) of 1:49.69. Besides that, total fermentable sugars yield (77.11%), was obtained at 170°C, 0.181N H2SO4, 6min 6s and SS ratio (w/v) of 1:40. Ridge analysis was employed to further verify the optimum conditions. Thus, this work provides fundamental data of the practical use of DPKC as low cost, high yield and environmental-friendly material for the production of mannose and other sugars.

Matched MeSH terms: Microwaves*
Preparation of activated carbon from sugarcane bagasse by microwave assisted activation for the remediation of semi-aerobic landfill leachate

Foo KY, Lee LK, Hameed BH

Bioresour Technol, 2013 Apr;134:166-72.
PMID: 23500574 DOI: 10.1016/j.biortech.2013.01.139

This study evaluates the sugarcane bagasse derived activated carbon (SBAC) prepared by microwave heating for the adsorptive removal of ammonical nitrogen and orthophosphate from the semi-aerobic landfill leachate. The physical and chemical properties of SBAC were examined by pore structural analysis, scanning electron microscopy, Fourier transform infrared spectroscopy and elemental analysis. The effects of adsorbent dosage, contact time and solution pH on the adsorption performance were investigated in a batch mode study at 30°C. Equilibrium data were favorably described by the Langmuir isotherm model, with a maximum monolayer adsorption capacity for ammonical nitrogen and orthophosphate of 138.46 and 12.81 mg/g, respectively, while the adsorption kinetic was best fitted to the pseudo-second-order kinetic model. The results illustrated the potential of sugarcane bagasse derived activated carbon for the adsorptive treatment of semi-aerobic landfill leachate.

Matched MeSH terms: Microwaves*
Drug release property of chitosan-pectinate beads and its changes under the influence of microwave

Wong TW, Nurjaya S

Eur J Pharm Biopharm, 2008 May;69(1):176-88.
PMID: 17980563

The effects of microwave irradiation on the drug release property of pectinate beads loaded internally with chitosan (chitosan-pectinate beads) were investigated against the pectinate beads and beads coacervated with chitosan externally (pectinate-chitosonium beads). These beads were prepared by an extrusion method using sodium diclofenac as the model water-soluble drug. The beads were subjected to microwave irradiation at 80 W for 5, 10, 21 and 40 min. The profiles of drug dissolution, drug content, drug-polymer interaction and polymer-polymer interaction were determined by drug dissolution testing, drug content assay, drug adsorption study, differential scanning calorimetry (DSC) and Fourier transform infra-red spectroscopy (FTIR) techniques. Treatment of pectinate beads by microwave did not lead to a decrease, but an increase in the extent of drug released at 4h of dissolution owing to reduced pectin-pectin interaction via the CO moiety of polymer. In addition, the extent of drug released from the pectinate beads could not be reduced merely through the coacervation of pectinate matrix with chitosan. The reduction in the extent of drug released from the pectinate-chitosonium beads required the treatment of these beads by microwave, following an increase in drug-polymer and polymer-polymer interaction in the matrix. The extent of drug released from the pectinate beads was reduced through incorporating chitosan directly into the interior of pectinate matrix, owing to drug-chitosan adsorption. Nonetheless, the treatment of chitosan-pectinate matrix by microwave brought about an increase in the extent of drug released unlike those of pectinate-chitosonium beads. Apparently, the loading of chitosan into the interior of pectinate matrix could effectively retard the drug release without subjecting the beads to the treatment of microwave. The microwave was merely essential to reduce the release of drug from pectinate beads when the chitosan was introduced to the pectinate matrix by means of coacervation. Under the influences of microwave, the drug release property of beads made of pectin and chitosan was mainly modulated via the CH, OH and NH moieties of polymers and drug, with CH functional group purported to retard while OH and NH moieties purported to enhance the drug released from the matrix.

Matched MeSH terms: Microwaves*
Aging and microwave effects on alginate/chitosan matrices

Wong TW, Chan LW, Kho SB, Heng PW

J Control Release, 2005 Jun 2;104(3):461-75.
PMID: 15911046

The influence of microwave irradiation on the drug release properties of freshly prepared and aged alginate, alginate-chitosan and chitosan beads was investigated. The beads were prepared by extrusion method with sulphathiazole as a model drug. The dried beads were subjected to microwave irradiation at 80 W for 10 min, 20 min or three consecutive cycles of 10 and 20 min, respectively. The profiles of drug dissolution, drug content, drug stability, drug polymorphism, drug-polymer interaction, polymer crosslinkage and complexation were determined by dissolution testing, drug content assay, differential scanning calorimetry and Fourier transform infra-red spectroscopy. The chemical stability of drug embedded in beads was unaffected by microwave conditions and length of storage time. The release property of drug was mainly governed by the extent of polymer interaction in beads. The aged alginate beads required intermittent cycles of microwave irradiation to induce drug release retarding effect in contrast to their freshly prepared samples. Unlike the alginate beads, the level of polymer interaction was higher in aged alginate-chitosan beads than the corresponding fresh beads. The drug release retarding property of aged alginate-chitosan beads could be significantly enhanced through subjecting the beads to microwave irradiation for 10 min. No further change in drug release from these beads was observed beyond 30 min of microwave irradiation. Unlike beads containing alginate, the rate and extent of drug released from the aged chitosan beads were higher upon treatment by microwave in spite of the higher degree of polymer interaction shown by the latter on prolonged storage. The observation suggested that the response of polymer matrix to microwave irradiation in induction of drug release retarding property was largely affected by the molecular arrangement of the polymer chains.

Matched MeSH terms: Microwaves*
Optimization and characterization of bio-oil produced by microwave assisted pyrolysis of oil palm shell waste biomass with microwave absorber

Mushtaq F, Abdullah TA, Mat R, Ani FN

Bioresour Technol, 2015 Aug;190:442-50.
PMID: 25794811 DOI: 10.1016/j.biortech.2015.02.055

In this study, solid oil palm shell (OPS) waste biomass was subjected to microwave pyrolysis conditions with uniformly distributed coconut activated carbon (CAC) microwave absorber. The effects of CAC loading (wt%), microwave power (W) and N2 flow rate (LPM) were investigated on heating profile, bio-oil yield and its composition. Response surface methodology based on central composite design was used to study the significance of process parameters on bio-oil yield. The coefficient of determination (R(2)) for the bio-oil yield is 0.89017 indicating 89.017% of data variability is accounted to the model. The largest effect on bio-oil yield is from linear and quadratic terms of N2 flow rate. The phenol content in bio-oil is 32.24-58.09% GC-MS area. The bio-oil also contain 1,1-dimethyl hydrazine of 10.54-21.20% GC-MS area. The presence of phenol and 1,1-dimethyl hydrazine implies that the microwave pyrolysis of OPS with carbon absorber has the potential to produce valuable fuel products.

Matched MeSH terms: Microwaves*
Physicochemical modulation of skin barrier by microwave for transdermal drug delivery

Wong TW, Nor Khaizan A

Pharm Res, 2013 Jan;30(1):90-103.
PMID: 22890987 DOI: 10.1007/s11095-012-0852-z

PURPOSE: To investigate mechanism of microwave enhancing drug permeation transdermally through its action on skin.
METHODS: Hydrophilic pectin-sulphanilamide films, with or without oleic acid (OA), were subjected to drug release and skin permeation studies. The skins were untreated or microwave-treated, and characterized by infrared spectroscopy, Raman spectroscopy, thermal, electron microscopy and histology techniques.
RESULTS: Skin treatment by microwave at 2450 MHz for 5 min promoted drug permeation from OA-free film without incurring skin damage. Skin treatment by microwave followed by film loaded with drug and OA resulted in permeation of all drug molecules that were released from film. Microwave exerted spacing of lipid architecture of stratum corneum into structureless domains which was unattainable by OA. It allowed OA to permeate stratum corneum and accumulate in dermis at a greater ease, and synergistically inducing lipid/keratin fluidization at hydrophobic C-H and hydrophilic O-H, N-H, C-O, C=O, C-N regimes of skin, and promoting drug permeation.
CONCLUSION: The microwave technology is evidently feasible for use in promotion of drug permeation across the skin barrier. It represents a new approach in transdermal drug delivery.

Matched MeSH terms: Microwaves*
Potential of jackfruit peel as precursor for activated carbon prepared by microwave induced NaOH activation

Foo KY, Hameed BH

Bioresour Technol, 2012 May;112:143-50.
PMID: 22414577 DOI: 10.1016/j.biortech.2012.01.178

The feasibility of preparing activated carbon (JPAC) from jackfruit peel, an industrial residue abundantly available from food manufacturing plants via microwave-assisted NaOH activation was explored. The influences of chemical impregnation ratio, microwave power and radiation time on the properties of activated carbon were investigated. JPAC was examined by pore structural analysis, scanning electron microscopy, Fourier transform infrared spectroscopy, nitrogen adsorption isotherm, elemental analysis, surface acidity/basicity and zeta potential measurements. The adsorptive behavior of JPAC was quantified using methylene blue as model dye compound. The best conditions resulted in JPAC with a monolayer adsorption capacity of 400.06 mg/g and carbon yield of 80.82%. The adsorption data was best fitted to the pseudo-second-order equation, while the adsorption mechanism was well described by the intraparticle diffusion model. The findings revealed the versatility of jackfruit peels as good precursor for preparation of high quality activated carbon.

Matched MeSH terms: Microwaves*
Microwave-assisted synthesis of sec/tert-butyl 2-arylbenzimidazoles and their unexpected antiproliferative activity towards ER negative breast cancer cells

Abdul Rahim AS, Salhimi SM, Arumugam N, Pin LC, Yee NS, Muttiah NN, et al.

J Enzyme Inhib Med Chem, 2013 Dec;28(6):1255-60.
PMID: 23061895 DOI: 10.3109/14756366.2012.729828

A new series of N-sec/tert-butyl 2-arylbenzimidazole derivatives was synthesised in 85-96% yields within 2-3.5 min by condensing ethyl 3-amino-4-butylamino benzoate with various substituted metabisulfite adducts of benzaldehyde under focused microwave irradiation. The benzimidazole analogues were characterised using (1)H NMR, (13)C NMR, high resolution MS and melting points. Evaluation of antiproliferative activity of the benzimidazole analogues against MCF-7 and MDA-MB-231 revealed several compounds with unexpected selective inhibitions of MDA-MB-231 in micromolar range. All analogues were found inactive towards MCF-7. The most potent inhibition against MDA-MB-231 human breast cancer cell line came from the unsubstituted 2-phenylbenzimidazole 10a.

Matched MeSH terms: Microwaves*
Preparation of activated carbon by microwave heating of langsat (Lansium domesticum) empty fruit bunch waste

Foo KY, Hameed BH

Bioresour Technol, 2012 Jul;116:522-5.
PMID: 22595094 DOI: 10.1016/j.biortech.2012.03.123

The feasibility of langsat empty fruit bunch waste for preparation of activated carbon (EFBLAC) by microwave-induced activation was explored. Activation with NaOH at the IR ratio of 1.25, microwave power of 600 W for 6 min produced EFBLAC with a carbon yield of 81.31% and adsorption uptake for MB of 302.48 mg/g. Pore structural analysis, scanning electron microscopy and Fourier transform infrared spectroscopy demonstrated the physical and chemical characteristics of EFBLAC. Equilibrium data were best described by the Langmuir isotherm, with a monolayer adsorption capacity of 402.06 mg/g, and the adsorption kinetics was well fitted to the pseudo-second-order equation. The findings revealed the potential to prepare high quality activated carbon from langsat empty fruit bunch waste by microwave irradiation.

Matched MeSH terms: Microwaves*
Characterization of hydroxypropylmethylcellulose films using microwave non-destructive testing technique

Anuar NK, Wui WT, Ghodgaonkar DK, Taib MN

J Pharm Biomed Anal, 2007 Jan 17;43(2):549-57.
PMID: 16978823

The applicability of microwave non-destructive testing (NDT) technique in characterization of matrix property of pharmaceutical films was investigated. Hydroxypropylmethylcellulose and loratadine were selected as model matrix polymer and drug, respectively. Both blank and drug loaded hydroxypropylmethylcellulose films were prepared using the solvent-evaporation method and were conditioned at the relative humidity of 25, 50 and 75% prior to physicochemical characterization using microwave NDT technique as well as ultraviolet spectrophotometry, differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FT-IR) techniques. The results indicated that blank hydroxypropylmethylcellulose film exhibited a greater propensity of polymer-polymer interaction at the O-H and C-H domains of the polymer chains upon conditioned at a lower level of relative humidity. In the case of loratadine loaded films, a greater propensity of polymer-polymer and/or drug-polymer interaction via the O-H moiety was mediated in samples conditioned at the lower level of relative humidity, and via the C-H moiety when 50% relative humidity was selected as the condition for sample storage. Apparently, the absorption and transmission characteristics of both blank and drug loaded films for microwave varied with the state of polymer-polymer and/or drug-polymer interaction involving the O-H and C-H moieties. The measurement of microwave NDT test at 8GHz was sensitive to the chemical environment involving O-H moiety while it was greatly governed by the C-H moiety in test conducted at a higher frequency band of microwave. Similar observation was obtained with respect to the profiles of microwave NDT measurements against the state of polymer-polymer and/or drug-polymer interaction of hydroxypropylmethylcellulose films containing chlorpheniramine maleate. The microwave NDT measurement is potentially suitable for use as an apparent indicator of the state of polymer-polymer and drug-polymer interaction of the matrix.

Matched MeSH terms: Microwaves*
Fulltext Biopolymers Regulate Silver Nanoparticle under Microwave Irradiation for Effective Antibacterial and Antibiofilm Activities

Velusamy P, Su CH, Venkat Kumar G, Adhikary S, Pandian K, Gopinath SC, et al.

PLoS One, 2016;11(6):e0157612.
PMID: 27304672 DOI: 10.1371/journal.pone.0157612

In the current study, facile synthesis of carboxymethyl cellulose (CMC) and sodium alginate capped silver nanoparticles (AgNPs) was examined using microwave radiation and aniline as a reducing agent. The biopolymer matrix embedded nanoparticles were synthesized under various experimental conditions using different concentrations of biopolymer (0.5, 1, 1.5, 2%), volumes of reducing agent (50, 100, 150 μL), and duration of heat treatment (30 s to 240 s). The synthesized nanoparticles were analyzed by scanning electron microscopy, UV-Vis spectroscopy, X-ray diffraction, and Fourier transform infrared spectroscopy for identification of AgNPs synthesis, crystal nature, shape, size, and type of capping action. In addition, the significant antibacterial efficacy and antibiofilm activity of biopolymer capped AgNPs were demonstrated against different bacterial strains, Staphylococcus aureus MTCC 740 and Escherichia coli MTCC 9492. These results confirmed the potential for production of biopolymer capped AgNPs grown under microwave irradiation, which can be used for industrial and biomedical applications.

Matched MeSH terms: Microwaves*

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