MyMedR

Fulltext Optimizing Bi2O3 and TiO2 to achieve the maximum non-linear electrical property of ZnO low voltage varistor

Abdollahi Y, Zakaria A, Aziz RS, Tamili SN, Matori KA, Shahrani NM, et al.

Chem Cent J, 2013;7:137.

PMID: 23938168 DOI: 10.1186/1752-153X-7-137

In fabrication of ZnO-based low voltage varistor, Bi2O3 and TiO2 have been used as former and grain growth enhancer factors respectively. Therefore, the molar ratio of the factors is quit important in the fabrication. In this paper, modeling and optimization of Bi2O3 and TiO2 was carried out by response surface methodology to achieve maximized electrical properties. The fabrication was planned by central composite design using two variables and one response. To obtain actual responses, the design was performed in laboratory by the conventional methods of ceramics fabrication. The actual responses were fitted into a valid second order algebraic polynomial equation. Then the quadratic model was suggested by response surface methodology. The model was validated by analysis of variance which provided several evidences such as high F-value (153.6), very low P-value (<0.0001), adjusted R-squared (0.985) and predicted R-squared (0.947). Moreover, the lack of fit was not significant which means the model was significant.

Fulltext Artificial neural network modeling of p-cresol photodegradation

Abdollahi Y, Zakaria A, Abbasiyannejad M, Masoumi HR, Moghaddam MG, Matori KA, et al.

Chem Cent J, 2013;7(1):96.

PMID: 23731706 DOI: 10.1186/1752-153X-7-96

The complexity of reactions and kinetic is the current problem of photodegradation processes. Recently, artificial neural networks have been widely used to solve the problems because of their reliable, robust, and salient characteristics in capturing the non-linear relationships between variables in complex systems. In this study, an artificial neural network was applied for modeling p-cresol photodegradation. To optimize the network, the independent variables including irradiation time, pH, photocatalyst amount and concentration of p-cresol were used as the input parameters, while the photodegradation% was selected as output. The photodegradation% was obtained from the performance of the experimental design of the variables under UV irradiation. The network was trained by Quick propagation (QP) and the other three algorithms as a model. To determine the number of hidden layer nodes in the model, the root mean squared error of testing set was minimized. After minimizing the error, the topologies of the algorithms were compared by coefficient of determination and absolute average deviation.

Fulltext Interactions between photodegradation components

Abdollahi Y, Zakaria A, Matori KA, Shameli K, Jahangirian H, Rezayi M, et al.

Chem Cent J, 2012;6(1):100.

PMID: 22967885 DOI: 10.1186/1752-153X-6-100

The interactions of p-cresol photocatalytic degradation components were studied by response surface methodology. The study was designed by central composite design using the irradiation time, pH, the amount of photocatalyst and the p-cresol concentration as variables. The design was performed to obtain photodegradation % as actual responses. The actual responses were fitted with linear, two factor interactions, cubic and quadratic model to select an appropriate model. The selected model was validated by analysis of variance which provided evidences such as high F-value (845.09), very low P-value (

Fulltext Semi-empirical study of ortho-cresol photo degradation in manganese-doped zinc oxide nanoparticles suspensions

Abdollahi Y, Zakaria A, Abdullah AH, Fard Masoumi HR, Jahangirian H, Shameli K, et al.

Chem Cent J, 2012 Aug 21;6(1):88.

PMID: 22909072 DOI: 10.1186/1752-153X-6-88

The optimization processes of photo degradation are complicated and expensive when it is performed with traditional methods such as one variable at a time. In this research, the condition of ortho-cresol (o-cresol) photo degradation was optimized by using a semi empirical method. First of all, the experiments were designed with four effective factors including irradiation time, pH, photo catalyst's amount, o-cresol concentration and photo degradation % as response by response surface methodology (RSM). The RSM used central composite design (CCD) method consists of 30 runs to obtain the actual responses. The actual responses were fitted with the second order algebraic polynomial equation to select a model (suggested model). The suggested model was validated by a few numbers of excellent statistical evidences in analysis of variance (ANOVA). The used evidences include high F-value (143.12), very low P-value (<0.0001), non-significant lack of fit, the determination coefficient (R2 = 0.99) and the adequate precision (47.067). To visualize the optimum, the validated model simulated the condition of variables and response (photo degradation %) be using a few number of three dimensional plots (3D). To confirm the model, the optimums were performed in laboratory. The results of performed experiments were quite close to the predicted values. In conclusion, the study indicated that the model is successful to simulate the optimum condition of o-cresol photo degradation under visible-light irradiation by manganese doped ZnO nanoparticles.

Fulltext Release behavior and toxicity profiles towards A549 cell lines of ciprofloxacin from its layered zinc hydroxide intercalation compound

Abdul Latip AF, Hussein MZ, Stanslas J, Wong CC, Adnan R

Chem Cent J, 2013;7:119.

PMID: 23849189 DOI: 10.1186/1752-153X-7-119

Layered hydroxides salts (LHS), a layered inorganic compound is gaining attention in a wide range of applications, particularly due to its unique anion exchange properties. In this work, layered zinc hydroxide nitrate (LZH), a family member of LHS was intercalated with anionic ciprofloxacin (CFX), a broad spectrum antibiotic via ion exchange in a mixture solution of water:ethanol.

Fulltext Biosynthesis of silver nanoparticles using Artocarpus elasticus stem bark extract

Abdullah NI, Ahmad MB, Shameli K

Chem Cent J, 2015;9:61.

PMID: 26528373 DOI: 10.1186/s13065-015-0133-0

Green approach in synthesizing metal nanoparticles has gain new interest from the researchers as metal nanoparticles were widely applied in medical equipment and household products. The use of plants in the synthesis of nanoparticles emerges as a cost effective and eco-friendly approach. A green synthetic route for the production of stable silver nanoparticles (Ag-NPs) by using aqueous silver nitrate as metal precursor and Artocarpus elasticus stem bark extract act both as reductant and stabilizer is being reported for the first time.

Fulltext A study on dispersion and characterisation of α-mangostin loaded pH sensitive microgel systems

Ahmad M, Yamin BM, Mat Lazim A

Chem Cent J, 2013;7:85.

PMID: 23680098 DOI: 10.1186/1752-153X-7-85

α-Mangostin was extracted with methanol from the rind of mangosteen fruit and purified by using silica gel column chromatography technique. The compound is characterised using infrared, (13)C and (1)H NMR as well as UV-vis spectroscopy. The α-mangostin dispersion in colloidal systems was studied by incorporating it with an ionic microgel, poly (N-Isopropylacrylamide)-co-2VP at different pH.

Fulltext Synthesis, inhibition effects and quantum chemical studies of a novel coumarin derivative on the corrosion of mild steel in a hydrochloric acid solution

Al-Azawi KF, Al-Baghdadi SB, Mohamed AZ, Al-Amiery AA, Abed TK, Mohammed SA, et al.

Chem Cent J, 2016;10:23.

PMID: 27134648 DOI: 10.1186/s13065-016-0170-3

BACKGROUND: The acid corrosion inhibition process of mild steel in 1 M HCl by 4-[(2-amino-1, 3, 4-thiadiazol-5-yl)methoxy]coumarin (ATC), has been investigated using weight loss technique and scanning electron microscopy (SEM). ATC was synthesized, and its chemical structure was elucidated and confirmed using spectroscopic techniques (infrared and nuclear magnetic resonance spectroscopy).

FINDINGS: The results indicated that inhibition efficiencies were enhanced with an increase in concentration of inhibitor and decreased with a rise in temperature. The adsorption equilibrium constant (K) and standard free energy of adsorption (ΔGads) were calculated. Quantum chemical parameters such as highest occupied molecular orbital energy, lowest unoccupied molecular orbital energy (EHOMO and ELUMO, respectively) and dipole moment (μ) were calculated and discussed. The results showed that the corrosion inhibition efficiency increased with an increase in both the EHOMO and μ values but with a decrease in the ELUMO value.

CONCLUSIONS: Our research show that the synthesized macromolecule represents an excellent inhibitor for materials in acidic solutions. The efficiency of this macromolecule had maximum inhibition efficiency up to 96 % at 0.5 mM and diminishes with a higher temperature degree, which is revealing of chemical adsorption. An inhibitor molecule were absorbed by metal surface and follow Langmuir isotherms low and establishes an efficient macromolecule inhibitor having excellent inhibitive properties due to entity of S (sulfur) atom, N (nitrogen) atom and O (oxygen) atom.

Fulltext Correlation between Fischer-Tropsch catalytic activity and composition of catalysts

Ali S, Mohd Zabidi NA, Subbarao D

Chem Cent J, 2011;5:68.

PMID: 22047220 DOI: 10.1186/1752-153X-5-68

This paper presents the synthesis and characterization of monometallic and bimetallic cobalt and iron nanoparticles supported on alumina. The catalysts were prepared by a wet impregnation method. Samples were characterized using temperature-programmed reduction (TPR), temperature-programmed oxidation (TPO), CO-chemisorption, transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM-EDX) and N2-adsorption analysis. Fischer-Tropsch synthesis (FTS) was carried out in a fixed-bed microreactor at 543 K and 1 atm, with H2/CO = 2 v/v and space velocity, SV = 12L/g.h. The physicochemical properties and the FTS activity of the bimetallic catalysts were analyzed and compared with those of monometallic cobalt and iron catalysts at similar operating conditions.H2-TPR analysis of cobalt catalyst indicated three temperature regions at 506°C (low), 650°C (medium) and 731°C (high). The incorporation of iron up to 30% into cobalt catalysts increased the reduction, CO chemisorption and number of cobalt active sites of the catalyst while an opposite trend was observed for the iron-riched bimetallic catalysts. The CO conversion was 6.3% and 4.6%, over the monometallic cobalt and iron catalysts, respectively. Bimetallic catalysts enhanced the CO conversion. Amongst the catalysts studied, bimetallic catalyst with the composition of 70Co30Fe showed the highest CO conversion (8.1%) while exhibiting the same product selectivity as that of monometallic Co catalyst. Monometallic iron catalyst showed the lowest selectivity for C5+ hydrocarbons (1.6%).

Fulltext Chemical composition and molecular structure of polysaccharide-protein biopolymer from Durio zibethinus seed: extraction and purification process

Amid BT, Mirhosseini H, Kostadinović S

Chem Cent J, 2012 Oct 14;6(1):117.

PMID: 23062269 DOI: 10.1186/1752-153X-6-117

BACKGROUND: The biological functions of natural biopolymers from plant sources depend on their chemical composition and molecular structure. In addition, the extraction and further processing conditions significantly influence the chemical and molecular structure of the plant biopolymer. The main objective of the present study was to characterize the chemical and molecular structure of a natural biopolymer from Durio zibethinus seed. A size-exclusion chromatography coupled to multi angle laser light-scattering (SEC-MALS) was applied to analyze the molecular weight (Mw), number average molecular weight (Mn), and polydispersity index (Mw/Mn).

RESULTS: The most abundant monosaccharide in the carbohydrate composition of durian seed gum were galactose (48.6-59.9%), glucose (37.1-45.1%), arabinose (0.58-3.41%), and xylose (0.3-3.21%). The predominant fatty acid of the lipid fraction from the durian seed gum were palmitic acid (C16:0), palmitoleic acid (C16:1), stearic acid (C18:0), oleic acid (C18:1), linoleic acid (C18:2), and linolenic acid (C18:2). The most abundant amino acids of durian seed gum were: leucine (30.9-37.3%), lysine (6.04-8.36%), aspartic acid (6.10-7.19%), glycine (6.07-7.42%), alanine (5.24-6.14%), glutamic acid (5.57-7.09%), valine (4.5-5.50%), proline (3.87-4.81%), serine (4.39-5.18%), threonine (3.44-6.50%), isoleucine (3.30-4.07%), and phenylalanine (3.11-9.04%).

CONCLUSION: The presence of essential amino acids in the chemical structure of durian seed gum reinforces its nutritional value.

Fulltext Influence of astaxanthin, emulsifier and organic phase concentration on physicochemical properties of astaxanthin nanodispersions

Anarjan N, Nehdi IA, Tan CP

Chem Cent J, 2013;7(1):127.

PMID: 23875816 DOI: 10.1186/1752-153X-7-127

The emulsification-evaporation method was used to prepare astaxanthin nanodispersions using a three-component emulsifier system composed of Tween 20, sodium caseinate and gum Arabic. Using Response-surface methodology (RSM), we studied the main and interaction effects of the major emulsion components, namely, astaxanthin concentration (0.02-0.38 wt %, x1), emulsifier concentration (0.2-3.8 wt %, x2) and organic phase (dichloromethane) concentration (2-38 wt %, x3) on nanodispersion characteristics. The physicochemical properties considered as response variables were: average particle size (Y1), PDI (Y2) and astaxanthin loss (Y3).

Fulltext Reaction of 2,6-dichloroquinone-4-chloroimide (Gibbs reagent) with permethrin - an optical sensor for rapid detection of permethrin in treated wood

Arip MN, Heng LY, Ahmad M, Hasbullah SA

Chem Cent J, 2013;7:122.

PMID: 23867006 DOI: 10.1186/1752-153X-7-122

A novel optical sensor for the rapid and direct determination of permethrin preservatives in treated wood was designed. The optical sensor was fabricated from the immobilisation of 2,6-dichloro-p-benzoquinone-4-chloroimide (Gibbs reagent) in nafion/sol-gel hybrid film and the mode of detection was based on absorption spectrophotometry. Physical entrapment was employed as a method of immobilisation.

Fulltext Compositional difference in antioxidant and antibacterial activity of all parts of the Carica papaya using different solvents

Asghar N, Naqvi SA, Hussain Z, Rasool N, Khan ZA, Shahzad SA, et al.

Chem Cent J, 2016;10:5.

PMID: 26848308 DOI: 10.1186/s13065-016-0149-0

Carica papaya is a well known medicinal plant used in the West and Asian countries to cope several diseases. Patients were advised to eat papaya fruit frequently during dengue fever epidemic in Pakistan by physicians. This study was conducted to establish Polyphenols, flavonoids and antioxidant potential profile of extracts of all major parts of the C. papaya with seven major solvents i.e. water, ethanol, methanol, n-butanol, dichloromethane, ethyl acetate, and n-hexane.

Fulltext Chemical composition, antioxidant and antimicrobial potential of essential oils from different parts of Daphne mucronata Royle

Ashraf I, Zubair M, Rizwan K, Rasool N, Jamil M, Khan SA, et al.

Chem Cent J, 2018 Dec 17;12(1):135.

PMID: 30556121 DOI: 10.1186/s13065-018-0495-1

This research work was executed to determine chemical composition, anti-oxidant and anti-microbial potential of the essential oils extracted from the leaves and stem of Daphne mucronata Royle. From leaves and stem oils fifty-one different constituents were identified through GC/MS examination. The antioxidant potential evaluated through DPPH free radical scavenging activity and %-inhibition of peroxidation in linoleic acid system. The stem's essential oil showed the good antioxidant activity as compared to leaves essential oil. Results of Antimicrobial activity revealed that both stem and leaves oils showed strong activity against Candida albicans with large inhibition zone (22.2 ± 0.01, 18.9 ± 0.20 mm) and lowest MIC values (0.98 ± 0.005, 2.44 ± 0.002 mg/mL) respectively. Leaves essential was also active against Escherichia coli with inhibition zone of 8.88 ± 0.01 mm and MIC values of 11.2 ± 0.40 mg/mL. These results suggested that the plant's essential oils would be a potential cradle for the natural product based antimicrobial as well as antioxidant agents.

Fulltext Optimization of reaction parameters in hydrothermal synthesis: a strategy towards the formation of CuS hexagonal plates

Auyoong YL, Yap PL, Huang X, Abd Hamid SB

Chem Cent J, 2013;7:67.

PMID: 23575312 DOI: 10.1186/1752-153X-7-67

For decades, copper sulphide has been renowned as the superior optical and semiconductor materials. Its potential applications can be ranged from solar cells, lithium-ion batteries, sensors, and catalyst systems. The synthesis methodologies of copper sulphide with different controlled morphology have been widely explored in the literature. Nevertheless, the understanding on the formation chemistry of CuS is still limited. The ultimate approach undertaking in this article is to investigate the formation of CuS hexagonal plates via the optimization of reaction parameters in hydrothermal reaction between copper (II) nitrate and sodium thiosulphate without appending any assistant agent.

Fulltext Optimization of phenolics and flavonoids extraction conditions of Curcuma Zedoaria leaves using response surface methodology

Azahar NF, Gani SSA, Mohd Mokhtar NF

Chem Cent J, 2017 Oct 02;11(1):96.

PMID: 29086882 DOI: 10.1186/s13065-017-0324-y

This study focused on maximizing the extraction yield of total phenolics and flavonoids from Curcuma Zedoaria leaves as a function of time (80-120 min), temperature (60-80 °C) and ethanol concentration (70-90 v/v%). The data were subjected to response surface methodology (RSM) and the results showed that the polynomial equations for all models were significant, did not show lack of fit, and presented adjusted determination coefficients (R(2)) above 99%, proving their suitability for prediction purposes. Using desirability function, the optimum operating conditions to attain a higher extraction of phenolics and flavonoids was found to be 75 °C, 92 min of extraction time and 90:10 of ethanol concentration ratios. Under these optimal conditions, the experimental values for total phenolics and flavonoids of Curcuma zedoaria leaves were 125.75 ± 0.17 mg of gallic acid equivalents and 6.12 ± 0.23 mg quercetin/g of extract, which closely agreed with the predicted values. Besides, in this study, the leaves from Curcuma zedoaria could be considered to have the strong antioxidative ability and can be used in various cosmeceuticals or medicinal applications.

Fulltext Stirring time effect of silver nanoparticles prepared in glutathione mediated by green method

Balavandy SK, Shameli K, Biak DR, Abidin ZZ

Chem Cent J, 2014;8(1):11.

PMID: 24524329 DOI: 10.1186/1752-153X-8-11

This study aims to investigate the influence of different stirring time for synthesis of silver nanoparticles in glutathione (GSH) aqueous solution. The silver nanoparticles (Ag-NPs) were prepared by green synthesis method using GSH as reducing agent and stabilizer, under moderate temperature at different stirring times. Silver nitrate (AgNO3) was taken as the metal precursor while Ag-NPs were prepared in the over reaction time.

Fulltext Structural and spectral investigations of the recently synthesized chalcone (E)-3-mesityl-1-(naphthalen-2-yl) prop-2-en-1-one, a potential chemotherapeutic agent

Barakat A, Al-Majid AM, Soliman SM, Mabkhot YN, Ali M, Ghabbour HA, et al.

Chem Cent J, 2015;9:35.

PMID: 26106444 DOI: 10.1186/s13065-015-0112-5

Chalcones (1,3-diaryl-2-propen-1-ones, represent an important subgroup of the polyphenolic family, which have shown a wide spectrum of medical and industrial application. Due to their redundancy in plants and ease of preparation, this category of molecules has inspired considerable attention for potential therapeutic uses. They are also effective in vivo as anti-tumor promoting, cell proliferating inhibitors and chemo preventing agents.

Fulltext Synthesis of molecular imprinting polymers for extraction of gallic acid from urine

Bhawani SA, Sen TS, Ibrahim MNM

Chem Cent J, 2018 Feb 21;12(1):19.

PMID: 29468431 DOI: 10.1186/s13065-018-0392-7

The molecularly imprinted polymers for gallic acid were synthesized by precipitation polymerization. During the process of synthesis a non-covalent approach was used for the interaction of template and monomer. In the polymerization process, gallic acid was used as a template, acrylic acid as a functional monomer, ethylene glycol dimethacrylate as a cross-linker and 2,2'-azobisisobutyronitrile as an initiator and acetonitrile as a solvent. The synthesized imprinted and non-imprinted polymer particles were characterized by using Fourier-transform infrared spectroscopy and scanning electron microscopy. The rebinding efficiency of synthesized polymer particles was evaluated by batch binding assay. The highly selective imprinted polymer for gallic acid was MIPI1 with a composition (molar ratio) of 1:4:20, template: monomer: cross-linker, respectively. The MIPI1 showed highest binding efficiency (79.50%) as compared to other imprinted and non-imprinted polymers. The highly selective imprinted polymers have successfully extracted about 80% of gallic acid from spiked urine sample.

Fulltext Antibacterial activity of silver bionanocomposites synthesized by chemical reduction route

Bin Ahmad M, Lim JJ, Shameli K, Ibrahim NA, Tay MY, Chieng BW

Chem Cent J, 2012;6(1):101.

PMID: 22967920 DOI: 10.1186/1752-153X-6-101

Displaying publications 1 - 20 of 92 in total