MyMedR

Displaying publications 61 - 80 of 284 in total

Abstract:

Sort:

Novel magnetic graphene oxide functionalized cyanopropyl nanocomposite as an adsorbent for the removal of Pb(II) ions from aqueous media: equilibrium and kinetic studies

Gabris MA, Jume BH, Rezaali M, Shahabuddin S, Nodeh HR, Saidur R

Environ Sci Pollut Res Int, 2018 Sep;25(27):27122-27132.
PMID: 30022389 DOI: 10.1007/s11356-018-2749-9

This work presents the synthesis of the novel silica-cyanopropyl functionalized magnetic graphene oxide (MGO/SiO2-CN) hybrid nanomaterial derived by sol-gel method as a cheap efficient magnetic sorbent for the removal of extremely hazardous lead ions from aqueous media. The integration of the magnetic property, the carbon substrate, and the nitrile (-C ≡ N) containing organic grafted silica matrix promoted the adsorption capability against lead ions along with its simple synthesis recovery and low cost. The prepared nanocomposite was comprehensively characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. Adsorption of lead was found to be pH dependent because of the charged nature of both analyte and adsorbent surface. Adsorption experiments were conducted under the optimum conditions, and the obtained experimental data from atomic absorption spectroscopy were analyzed using the popular isothermal models namely Langmuir, Freundlich, and Dubinin-Radushkevich isotherms as well as kinetically studied and evaluated for adsorption standard free energy (E). The experimental results have demonstrated the enhanced adsorption capability of the proposed sorbent nanocomposite for lead ion removal with the maximum adsorption capacity of 111.11 mg/g at pH 5.0. The proposed mechanism of lead adsorption was mainly attributed to the complexation of lead positive ions with the grafted -C ≡ N bond. The synergistic effect of the combination of three components (i.e., the magnetic graphene oxide matrix, the triple bond containing organic moiety, and the inorganic porous silica framework) excelled the adsorption capability and proved to be a good candidate as adsorbent for the removal of lead ions.

Matched MeSH terms: Ions
Imidazolium-based ionic liquid salts: 3,3'-dimethyl-1,1'-(1,4-phenylenedimethylene)diimidazolium bis(tetrafluoroborate) and 3,3'-di-n-butyl-1,1'-(1,4-phenylenedimethylene)diimidazolium bis(trifluoromethanesulfonate)

Ganesan K, Alias Y, Ng SW

Acta Crystallogr C, 2008 Sep;64(Pt 9):o478-80.
PMID: 18758014 DOI: 10.1107/S0108270108023111

Crystallization of the ionic liquid 3,3'-dimethyl-1,1'-(1,4-phenylenedimethylene)diimidazolium bis(tetrafluoroborate), C(16)H(20)N(4)(2+).2BF(4)(-), (I), from its solution in water has permitted the first single-crystal study of an imidazolium-based ionic liquid having a tetrafluoroborate ion as counter-ion. Despite the expectation that the anion would not participate in nonclassical hydrogen bonding, the ionic liquid features C-H...F hydrogen bonds. The dication lies about a center of inversion. The ionic liquid 3,3'-di-n-butyl-1,1'-(1,4-phenylenedimethylene)diimidazolium bis(trifluoromethanesulfonate), C(22)H(32)N(4)(2+).2CF(3)SO(3)(-), (II), features both C-H...F and C-H...O hydrogen bonds.

Matched MeSH terms: Anions; Ions
Waste-to-Resource: New application of modified mine silicate waste to remove Pb2+ ion and methylene blue dye, adsorption properties, mechanism of action and recycling

Ghaedi S, Seifpanahi-Shabani K, Sillanpää M

Chemosphere, 2022 Apr;292:133412.
PMID: 34974049 DOI: 10.1016/j.chemosphere.2021.133412

Currently, heavy metals and dyes are some of the most critical pollutants in the aquatic environment. So, in this paper "waste-to-resource conversion", as a new application of modified mine silicate waste to remove Pb2+ ion and methylene blue (MB) dye, adsorption properties, mechanism of action and recycling were studied. Silicate wastes are located in the alteration zone and the margin of molybdenum ore, these wastes are under the influence of hydrothermal solutions which are impregnated with iron and manganese ions. Hence, acid and base modifications have been commonly used. So, in this study, a highly porous nanostructure of modified silicate waste was used to remove MB and Pb2+ ion, in subsequent to our previous study on the application of the raw material of the same in the removal of malachite green. Acid, base, and acid/base treatments were used to activate and modify the adsorbent. Results show a significantly higher potential of modified adsorbent in the removal of MB and Pb2+ compared to the raw material. According to the isotherm and kinetic studies for MB and Pb2+ the Langmuir and Temkin and pseudo-second-order models were investigated with experimental data. Modified nanomaterial was used for several adsorption and desorption processes, without a significant decrease in the capability of the adsorbent in the removal of MB and Pb2+ pollutants. Leached iron and manganese ions (as production of modification) are deposited in the form of sludge using a simple pH adjustment and precipitation process and can be used to recover iron and manganese metals in the long run. The comparison of monolayer adsorption capacity using for Pb2+ ion and MB dye are as ((untreated SW: 29.41, 1.05); (NaOH treated: 21.74, 100); (Nitric Acid treated: 16.67, 142.86); (Citric Acid treated: 40, 125); (Nitric/Citric Acids treated: 15.63, 111.11) and (Nitric/Citric Acids/NaOH treated: 15.15, 83.33)), respectively. Higher adsorption capacity and re-generable properties of this adsorbent suggest the usage of this natural and abundant mine waste to treat wastewater containing toxic elements and dyes.

Matched MeSH terms: Ions
Isolation and characterization of a mo -reducing bacterium

Ghani B, Takai M, Hisham NZ, Kishimoto N, Ismail AK, Tano T, et al.

Appl Environ Microbiol, 1993 Apr;59(4):1176-80.
PMID: 16348915

A Mo -reducing bacterium (strain 48), which grew on medium supplemented with 200 mM Mo, was isolated from stream water obtained from Chengkau, Malaysia. The chemical properties of strain 48 conform to the characteristics of Enterobacter cloacae. Under anaerobic conditions in the glucose-yeast extract medium containing phosphate ion (2.9 mM) and Mo (10 mM), the bacterium reduced Mo to form molybdenum blue. Approximately 27% of Mo added to the medium was reduced after 28 h of cultivation. The reduction of Mo with glucose as an electron donor was strongly inhibited by iodoacetic acid, sodium fluoride, and sodium cyanide, suggesting an involvement of the glycolytic pathway and electron transport in Mo reduction. NADH and N,N,N',N' -tetramethyl-p-phenylenediamine served as electron donors for Mo reduction. When NADH was used as an electron donor, at first cytochrome b in the cell extract was reduced, and then molybdenum blue was formed. Sodium cyanide strongly inhibited Mo reduction by NADH (5 mM) but not the reduction of cytochrome b in the cell extract, suggesting that the reduced component of the electron transport system after cytochrome b serves as an electron donor for Mo reduction. Both ferric and stannous ions strongly enhanced the activity of Mo reduction by NADH.

Matched MeSH terms: Ions
Comparative study of the antioxidant activities of some lipase-catalyzed alkyl dihydrocaffeates synthesized in ionic liquid

Gholivand S, Lasekan O, Tan CP, Abas F, Wei LS

Food Chem, 2017 Jun 01;224:365-371.
PMID: 28159281 DOI: 10.1016/j.foodchem.2016.12.075

The solubility limitations of phenolic acids in many lipidic environments are now greatly improved by their enzymatic esterification in ionic liquids (ILs). Herein, four different ILs were tested for the esterification of dihydrocaffeic acid with hexanol and the best IL was selected for the synthesis of four other n-alkyl esters with different chain-lengths. The effect of alkyl chain length on the anti-oxidative properties of the resulted purified esters was investigated using β-carotene bleaching (BCB) and free radical scavenging method DPPH and compared with butylated hydroxytoluene (BHT) as reference compound. All four esters (methyl, hexyl, dodecyl and octadecyl dihydrocaffeates) exhibited relatively strong radical scavenging abilities. The scavenging activity of the test compounds was in the following order: methyl ester>hexyl ester⩾dodecyl ester>octadecyl ester>BHT while the order for the BCB anti-oxidative activity was; BHT>octadecyl ester>dodecyl ester>hexyl ester>methyl ester.

Matched MeSH terms: Ions/chemistry*
Chitosan/(polyvinyl alcohol)/zeolite electrospun composite nanofibrous membrane for adsorption of Cr6+, Fe3+ and Ni2

Habiba U, Afifi AM, Salleh A, Ang BC

J Hazard Mater, 2017 Jan 15;322(Pt A):182-194.
PMID: 27436300 DOI: 10.1016/j.jhazmat.2016.06.028

In this study, chitosan/polyvinyl alcohol (PVA)/zeolite nanofibrous composite membrane was fabricated via electrospinning. First, crude chitosan was hydrolyzed with NaOH for 24h. Afterward, hydrolyzed chitosan solution was blended with aqueous PVA solution in different weight ratios. Morphological analysis of chitosan/PVA electrospun nanofiber showed a defect-free nanofiber material with 50:50 weight ratio of chitosan/PVA. Subsequently, 1wt.% of zeolite was added to this blended solution of 50:50 chitosan/PVA. The resulting nanofiber was characterized with field emission scanning electron microscopy, X-Ray diffraction, Fourier transform infrared spectroscopy, swelling test, and adsorption test. Fine, bead-free nanofiber with homogeneous nanofiber was electrospun. The resulting membrane was stable in distilled water, acidic, and basic media in 20 days. Moreover, the adsorption ability of nanofibrous membrane was studied over Cr (VI), Fe (III), and Ni (II) ions using Langmuir isotherm. Kinetic parameters were estimated using the Lagergren first-order, pseudo-second-order, and intraparticle diffusion kinetic models. Kinetic study showed that adsorption rate was high. However, the resulting nanofiber membrane showed less adsorption capacity at high concentration. The adsorption capacity of nanofiber was unaltered after five recycling runs, which indicated the reusability of chitosan/PVA/zeolite nanofibrous membrane. Therefore, chitosan/PVA/zeolite nanofiber can be a useful material for water treatment at moderate concentration of heavy metals.

Matched MeSH terms: Ions
Effect of deacetylation on property of electrospun chitosan/PVA nanofibrous membrane and removal of methyl orange, Fe(III) and Cr(VI) ions

Habiba U, Siddique TA, Talebian S, Lee JJL, Salleh A, Ang BC, et al.

Carbohydr Polym, 2017 Dec 01;177:32-39.
PMID: 28962774 DOI: 10.1016/j.carbpol.2017.08.115

In this study, effect of degree of deacetylation on property and adsorption capacity of chitosan/polyvinyl Alcohol electrospun membrane has been investigated. Resulting nanofibers were characterized by FESEM, FTIR, XRD, TGA, tensile testing, weight loss test and adsorption test. FESEM result shows, finer nanofiber was fabricated from 42h hydrolyzed chitosan and PVA blend solution. FTIR and XRD result showed a strong interaction between chitosan and polyvinyl alcohol. Higher tensile strength was observed for the nanofiber having 42h hydrolyzed chitosan. Blend solution of chitosan/PVA having low DD chitosan had higher viscosity. The nanofibrous membrane was stable in distilled water, acidic and basic medium. The isotherm study shows that the adsorption capacity (qm) of nanofiber containing higher DD chitosan was higher for Cr(VI). In contrary, the membrane containing chitosan with lower DD showed the higher adsorption capacity for Fe(III) and methyl orange. Moreover, the effect of DD on removal percentage of adsorbate was dependent on the initial concentration of the adsorbate.

Matched MeSH terms: Ions/chemistry
An assessment of the pH changes and metal ions released into artificial saliva by fake orthodontic braces

Haleem R, Shafiai NAA, Noor SNFM

BMC Oral Health, 2023 Sep 16;23(1):669.
PMID: 37717000 DOI: 10.1186/s12903-023-03339-7

BACKGROUND: This present study assesses changes in the pH as well as the metal ions that fake braces release into artificial saliva (AS) using a pH meter and inductively coupled plasma atomic emission spectroscopy (ICP-AES), respectively.
METHODS: Three sets of fake archwires (AWs) and brackets (Bs) as well as a set of controls were immersed in AS and placed in an incubator shaker at 50 rpm and 37°C. At Days 0, 1, 7, 14, 21, and 28, the pH of the AS medium was measured and 3.0 ml of AS was collected and stored at -20°C for elemental analysis.
RESULTS: Significant changes in pH were observed on Days 0, 1, 7, 14, 21, and 28 in the AS of the AW group. However, these changes were only observed in the B group on Days 0 and 7. The fake samples released a large quantity of sodium (Na), potassium (K), and calcium (Ca) ions, at concentrations exceeding 100 mg/L, post-28 days of immersion. The control and fake braces samples released other ions; such as lithium (Li), magnesium (Mg), barium (Ba), chromium (Cr), copper (Cu), lead (Pb), and aluminium (Al); at concentrations that did not exceed 10 mg/L.
CONCLUSIONS: The pH of the AS of all the samples increased post-incubation. Only 10 ions; namely, Na, Li, K, Mg, Ca, Ba, Cr, Cu, Pb, and Al; were detected in the AS.

Matched MeSH terms: Ions
Fulltext Plasticized Polymer Blend Electrolyte Based on Chitosan for Energy Storage Application: Structural, Circuit Modeling, Morphological and Electrochemical Properties

Hamsan MH, Nofal MM, Aziz SB, Brza MA, Dannoun EMA, Murad AR, et al.

Polymers (Basel), 2021 Apr 11;13(8).
PMID: 33920346 DOI: 10.3390/polym13081233

Chitosan (CS)-dextran (DN) biopolymer electrolytes doped with ammonium iodide (NH4I) and plasticized with glycerol (GL), then dispersed with Zn(II)-metal complex were fabricated for energy device application. The CS:DN:NH4I:Zn(II)-complex was plasticized with various amounts of GL and the impact of used metal complex and GL on the properties of the formed electrolyte were investigated.The electrochemical impedance spectroscopy (EIS) measurements have shown that the highest conductivity for the plasticized system was 3.44 × 10-4 S/cm. From the x-ray diffraction (XRD) measurements, the plasticized electrolyte with minimum degree of crystallinity has shown the maximum conductivity. The effect of (GL) plasticizer on the film morphology was studied using FESEM. It has been confirmed via transference number analysis (TNM) that the transport mechanism in the prepared electrolyte is predominantly ionic in nature with a high transference number of ion (ti)of 0.983. From a linear sweep voltammetry (LSV) study, the electrolyte was found to be electrochemically constant as the voltage sweeps linearly up to 1.25 V. The cyclic voltammetry (CV) curve covered most of the area of the current-potential plot with no redox peaks and the sweep rate was found to be affecting the capacitance. The electric double-layer capacitor (EDLC) has shown a great performance of specific capacitance (108.3 F/g), ESR(47.8 ohm), energy density (12.2 W/kg) and power density (1743.4 W/kg) for complete 100 cycles at a current density of 0.5 mA cm-2.

Matched MeSH terms: Ions
A sensitive, selective and rapid determination of lead(II) ions in real-life samples using an electrochemically reduced graphene oxide-graphite reinforced carbon electrode

Hamsawahini K, Sathishkumar P, Ahamad R, Yusoff AR

Talanta, 2015 Nov 1;144:969-76.
PMID: 26452915 DOI: 10.1016/j.talanta.2015.07.049

In this study, a sensitive and cost-effective electrochemically reduced graphene oxide (ErGO) on graphite reinforced carbon (GRC) was developed for the detection of lead (Pb(II)) ions present in the real-life samples. A film of graphene oxide (GO) was drop-casted on GRC and their electrochemical properties were investigated using cyclic voltammetry (CV), amperometry and square wave voltammetry (SWV). Factors influencing the detection of Pb(II) ions, such as grades of GRC, constant applied cathodic potential (CACP), concentration of hydrochloric acid and drop-casting drying time were optimised. GO is irreversibly reduced in the range of -0.7 V to -1.6 V vs Ag/AgCl (3 M) in acidic condition. The results showed that the reduction behaviour of GO contributed to the high sensitivity of Pb(II) ions detection even at nanomolar level. The ErGO-GRC showed the detection limit of 0.5 nM and linear range of 3-15 nM in HCl (1 M). The developed electrode has potential to be a good candidate for the determination of Pb(II) ions in different aqueous system. The proposed method gives a good recovery rate of Pb(II) ions in real-life water samples such as tap water and river water.

Matched MeSH terms: Ions
Fulltext Toward Enhanced State of Charge Estimation of Lithium-ion Batteries Using Optimized Machine Learning Techniques

Hannan MA, Lipu MSH, Hussain A, Ker PJ, Mahlia TMI, Mansor M, et al.

Sci Rep, 2020 Mar 13;10(1):4687.
PMID: 32170100 DOI: 10.1038/s41598-020-61464-7

State of charge (SOC) is a crucial index used in the assessment of electric vehicle (EV) battery storage systems. Thus, SOC estimation of lithium-ion batteries has been widely investigated because of their fast charging, long-life cycle, and high energy density characteristics. However, precise SOC assessment of lithium-ion batteries remains challenging because of their varying characteristics under different working environments. Machine learning techniques have been widely used to design an advanced SOC estimation method without the information of battery chemical reactions, battery models, internal properties, and additional filters. Here, the capacity of optimized machine learning techniques are presented toward enhanced SOC estimation in terms of learning capability, accuracy, generalization performance, and convergence speed. We validate the proposed method through lithium-ion battery experiments, EV drive cycles, temperature, noise, and aging effects. We show that the proposed method outperforms several state-of-the-art approaches in terms of accuracy, adaptability, and robustness under diverse operating conditions.

Matched MeSH terms: Ions
Fulltext Benzyl and methyl fatty hydroxamic acids based on palm kernel oil as chelating agent for liquid-liquid iron(III) extraction

Haron MJ, Jahangirian H, Silong S, Yusof NA, Kassim A, Rafiee-Moghaddam R, et al.

Int J Mol Sci, 2012;13(2):2148-59.
PMID: 22408444 DOI: 10.3390/ijms13022148

Liquid-liquid iron(III) extraction was investigated using benzyl fatty hydroxamic acids (BFHAs) and methyl fatty hydroxamic acids (MFHAs) as chelating agents through the formation of iron(III) methyl fatty hydroxamate (Fe-MFHs) or iron(III) benzyl fatty hydroxamate (Fe-BFHs) in the organic phase. The results obtained under optimized conditions, showed that the chelating agents in hexane extract iron(III) at pH 1.9 were realized effectively with a high percentage of extraction (97.2% and 98.1% for MFHAs and BFHAs, respectively). The presence of a large amount of Mg(II), Ni(II), Al(III), Mn(II) and Co(II) ions did affect the iron(III) extraction. Finally stripping studies for recovering iron(III) from organic phase (Fe-MFHs or Fe-BFHs dissolved in hexane) were carried out at various concentrations of HCl, HNO(3) and H(2)SO(4). The results showed that the desired acid for recovery of iron(III) was 5 M HCl and quantitative recovery of iron(III) was achieved from Fe(III)-MFHs and Fe(III)-BFHs solutions in hexane containing 5 mg/L of Fe(III).

Matched MeSH terms: Ions
Synthesis and properties of poly(hydroxamic acid) from crosslinked poly(methacrylate)

Haron MJ, Wan Md ZW, Desa MZ, Kassim A

Talanta, 1994 May;41(5):805-7.
PMID: 18966002

Poly(hydroxamic acid) chelating ion-exchange resin was prepared from crosslinked poly(methacrylate) beads. The starting polymer was prepared by a suspension polymerization of methacrylate and divinyl benzene. Conversion of the ester groups into the hydroxamic acid was carried out by treatment with hydroxylamine in an alkaline solution. Hydroxamic acid capacity of the product was 2.71 mmol/g. The resin exhibited high affinity towards Fe(III) and Pb ions and its capacities for Fe(III), Pb, Cu, Ni and Co ions were pH dependent. The ability of the resin to carry out the separation of Fe(III)CuCo/Ni and PbNi ions is also reported.

Matched MeSH terms: Ions
Optical biodetection of cadmium and lead ions in water

Haron S, Ray AK

Med Eng Phys, 2006 Dec;28(10):978-81.
PMID: 17018258

A three layer waveguiding silicon dioxide (SiO(2))/silicon nitride (Si(3)N(4))/SiO(2) structure on silicon substrate was proposed as an optically efficient biosensor for calibration of heavy metal ions in drinking water. The catalytic activities of urease and acetylcholine esterase (AchE) were inhibited by the presence of cadmium (Cd(2+)) and lead (Pb(2+)) ions. The detection limit as low as 1 ppb was achieved by employing the technique of total reflection at the interface between the Si(3)N(4) core and composite polyelectrolyte self-assembled (PESA) membranes containing cyclotetrachromotropylene (CTCT) as an indicator.

Matched MeSH terms: Ions
Fulltext Novel DNA Biosensor for Direct Determination of Carrageenan

Hassan RA, Heng LY, Tan LL

Sci Rep, 2019 04 23;9(1):6379.
PMID: 31015498 DOI: 10.1038/s41598-019-42757-y

A novel disposable electrochemical biosensor based on immobilized calf thymus double-stranded DNA (dsDNA) on the carbon-based screen-printed electrode (SPE) is developed for rapid biorecognition of carrageenan by using methylene blue (MB) redox indicator. The biosensor protocol for the detection of carrageenan is based on the concept of competitive binding of positively charged MB to the negatively charged dsDNA and carrageenan. The decrement in the MB cathodic peak current (ipc) signal as a result of the released MB from the immobilized dsDNA, and attracted to the carrageenan can be monitored via differential pulse voltammetry (DPV). The biosensor showed high sensitivity and selectivity to carrageenan at low concentration without interference from other polyanions such as alginate, gum arabic and starch. Calibration of the biosensor with carrageenan exhibited an excellent linear dependence from 1-10 mg L-1 (R2 = 0.98) with a detection limit of 0.08 mg L-1. The DNA-based carrageenan biosensor showed satisfactory reproducibility with 5.6-6.9% (n = 3) relative standard deviations (RSD), and possessing several advantages such as simplicity, fast and direct application to real sample analysis without any prior extensive sample treatments, particularly for seaweeds and food analyses.

Matched MeSH terms: Ions
Fulltext Rapid determination of kappa-carrageenan using a biosensor from immobilized Pseudomonas carrageenovora cells

Hassan RA, Heng LY, Ahmad A, Tan LL

PLoS One, 2019;14(4):e0214580.
PMID: 30990847 DOI: 10.1371/journal.pone.0214580

A potentiometric whole cell biosensor based on immobilized marine bacterium, Pseudomonas carrageenovora producing κ-carrageenase and glycosulfatase enzymes for specific and direct determination of κ-carrageenan, is described. The bacterial cells were immobilized on the self-plasticized hydrogen ion (H+)-selective acrylic membrane electrode surface to form a catalytic layer. Hydrogen ionophore I was incorporated in the poly(n-butyl acrylate) [poly(nBA)] as a pH ionophore. Catalytic decomposition of κ-carrageenan by the bienzymatic cascade reaction produced neoagarobiose, an inorganic sulfate ion and a proton. The latter was detectable by H+ ion transducer for indirect potentiometric quantification of κ-carrageenan concentration. The use of a disposable screen-printed Ag/AgCl electrode (SPE) provided no cleaning requirement and enabled κ-carrageenan detection to be carried out conveniently without cross contamination in a complex food sample. The SPE-based microbial biosensor response was found to be reproducible with high reproducibility and relative standard deviation (RSD) at 2.6% (n = 3). The whole cell biosensor demonstrated a broad dynamic linear response range to κ-carrageenan from 0.2-100 ppm in 20 mM phosphate buffer saline (PBS) at pH 7.5 with a detection limit at 0.05 ppm and a Nernstian sensitivity of 58.78±0.87 mV/decade (R2 = 0.995). The biosensor showed excellent selectivity towards κ-carrageenan compared to other types of carrageenans tested e.g. ι-carrageenan and λ-carrageenan. No pretreatment to the food sample was necessary when the developed whole cell biosensor was employed for direct assay of κ-carrageenan in dairy product.

Matched MeSH terms: Ions
Fulltext The properties, compositions and qualities of Yellowstripe scad (Selaroides Leptolepis) and its liquid protein hydrolysate based on different enzyme concentrations, hydrolysis time and choice of buffer

Hau, E.H., Amiza, M.A., Zainol, M.K., Mohd Zin, Z.

International Food Research Journal, 2018;25(3):1174-1180.
MyJurnal

This study aimed to determine the best parameters (types of buffer, hydrolysis time and enzyme concentration) used to produce good quality of liquid protein hydrolysate from Yellowstripe scad in terms of high yield, protein content and concentration. The choice of buffer (sodium or potassium buffer), hydrolysis time (1 h, 2 h, 3 h or 4 h) and enzymes concentrations (0.5%, 1.0%, 1.5% and 2.0%) were investigated. The results obtained from two way ANOVA showed that these parameters had significant difference (p

Matched MeSH terms: Anions; Ions
Bacterial membrane disruption in food pathogens by Psidium guajava leaf extracts

Henie, E.F.P., Zaiton, H., Suhaila, M.

International Food Research Journal, 2009;16(3):297-311.
MyJurnal

The mode of action and activities of guava leaf extracts against various food pathogens were studied. The killing kinetics, viability and cell leakage of Kocuria rhizophila, Salmonella typhimurium, Listeria monocytogenes and Escherichia coli O157:H7, measured after exposure to guava methanolic extracts (GME) revealed a significantly higher (p≤0.05) release of bacterial nucleic acids, K+ ions and protein than that of untreated microbes, indicating disruption of the bacterial membrane. GME caused a significantly higher (p≤0.05) release of RNA in gramnegatives compared to gram-positives. GME caused a relatively small but significant release of pyrines and pyrimidines in all organisms investigated. GME probably disrupted the integrity of the Gram-negative microorganism lipopolysaccharide (LPS) layer. Unlike all the other microorganisms tested, E. coli O157:H7, demonstrated the lowest protein leakage, the highest K+ leakage, the highest pyrines and pyrimidines leakage within the first 10 min of extract exposure, but the lowest after 30 minutes, which may indicate their good homeostasis ability or adaptability. Understanding the mode of action of this flavonoid rich guava leaf extract, would help develop it as an alternative biodegradable and safe, antimicrobial for food and medicine, and as a by-product of the guava industry.

Matched MeSH terms: Ions
Fulltext Mineral composition and pasting properties of banana pseudo-stem flour from Musa acuminata X balbisiana cv. Awak grown locally in Perak, Malaysia

Ho, L.H., Noor Aziah, A.A., Rajeev Bhat

International Food Research Journal, 2012;19(4):1479-1485.
MyJurnal

The banana pseudo-stem is not currently utilised in the food industry. The aim of this research was to investigate the chemical and pasting profile of banana pseudo-stem flour (BPF). Wheat flour were substituted with BPF (0, 5, 15 and 30%) and the pasting profile were determined. Results from mineral analysis showed that the levels of sodium (Na), potassium (K), calcium (Ca), magnesium (Mg) and phosphorus (P) were higher than those of iron (Fe), zinc (Zn) and manganese (Mn). The BPF had a 0.04% total titratable acidity (TTA) and a total soluble solid (TSS) of 1.30⁰ Brix with pH 5.41. BPF contained 28.26% total starch, 12.81% resistant starch and a total digestible starch value of 15.45%. An increased substitution level of BPF into wheat flour significantly (p

Matched MeSH terms: Ions
Paper-based capacitive sensors for identification and quantification of chemicals at the point of care

Hu J, Yew CT, Chen X, Feng S, Yang Q, Wang S, et al.

Talanta, 2017 Apr 01;165:419-428.
PMID: 28153277 DOI: 10.1016/j.talanta.2016.12.086

The identification and quantification of chemicals play a vital role in evaluation and surveillance of environmental health and safety. However, current techniques usually depend on costly equipment, professional staff, and/or essential infrastructure, limiting their accessibility. In this work, we develop paper-based capacitive sensors (PCSs) that allow simple, rapid identification and quantification of various chemicals from microliter size samples with the aid of a handheld multimeter. PCSs are low-cost parallel-plate capacitors (~$0.01 per sensor) assembled from layers of aluminum foil and filter paper via double-sided tape. The developed PCSs can identify different kinds of fluids (e.g., organic chemicals) and quantify diverse concentrations of substances (e.g., heavy metal ions) based on differences in dielectric properties, including capacitance, frequency spectrum, and dielectric loss tangent. The PCS-based method enables chemical identification and quantification to take place much cheaply, simply, and quickly at the point-of-care (POC), holding great promise for environmental monitoring in resource-limited settings.

Matched MeSH terms: Ions

Filters

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links