Displaying publications 1 - 20 of 42 in total

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  1. Letchumanan VP, Lim KF, Mohamad AB
    Med J Malaysia, 2013 Oct;68(5):405-9.
    PMID: 24632870 MyJurnal
    INTRODUCTION: Spontaneous rupture is a dramatic presentation of HCC and it carries high mortality rate. To study the outcomes of ruptured HCC patients managed at a tertiary referral centre in Malaysia.
    METHODS: A retrospective review of all ruptured HCC patients managed as inpatient at the Department of Hepatobiliary Surgery, Hospital Selayang between January 2001 and December 2010. Data was retrieved from the hospital electronic medical records, Powerchart (Cerner Corporation Inc., USA) and supplemented with registry from Interventional Radiology record of chemoembolization and registry from hepatobiliary operative surgery records.
    RESULTS: There were 22 patients admitted with confirmed diagnosis of ruptured HCC over 10 years period. The common clinical findings on presentation were abdominal pain and presence of shock (36.4%). The mortality rate was 81.8% with only four patients noted to be alive during the follow up. One year overall survival for ER and DR are 40.0% and 72.7% respectively and the median survival in patients treated with DR was 433.3 days whereas it was 212.5 days in ER group.
    CONCLUSIONS: This study supports the clinical practice of TAE should be the first line treatment followed by staged surgery in suitable candidates with ruptured HCC.
  2. Salman SD, Kadhum AA, Takriff MS, Mohamad AB
    ScientificWorldJournal, 2014;2014:543231.
    PMID: 24605055 DOI: 10.1155/2014/543231
    Numerical investigation has been carried out on heat transfer and friction factor characteristics of copper-water nanofluid flow in a constant heat-fluxed tube with the existence of new configuration of vortex generator using Computational Fluid Dynamics (CFD) simulation. Two types of swirl flow generator: Classical twisted tape (CTT) and Parabolic-cut twisted tape (PCT) with a different twist ratio (y = 2.93, 3.91 and 4.89) and different cut depth (w = 0.5, 1.0 and 1.5 cm) with 2% and 4% volume concentration of CuO nanofluid were used for simulation. The effect of different parameters such as flow Reynolds number, twist ratio, cut depth and nanofluid were considered. The results show that the enhancement of heat transfer rate and the friction factor induced by the Classical (CTT) and Parabolic-cut (PCT) inserts increases with twist ratio and cut depth decreases. The results also revealed that the heat transfer enhancement increases with an increase in the volume fraction of the CuO nanoparticle. Furthermore, the twisted tape with twist ratio (y = 2.93) and cut depth w = 0.5 cm offered 10% enhancement of the average Nusselt number with significant increases in friction factor than those of Classical twisted tape.
  3. Salman SD, Kadhum AA, Takriff MS, Mohamad AB
    ScientificWorldJournal, 2013;2013:492762.
    PMID: 24078795 DOI: 10.1155/2013/492762
    Numerical investigation of the heat transfer and friction factor characteristics of a circular fitted with V-cut twisted tape (VCT) insert with twist ratio (y = 2.93) and different cut depths (w = 0.5, 1, and 1.5 cm) were studied for laminar flow using CFD package (FLUENT-6.3.26). The data obtained from plain tube were verified with the literature correlation to ensure the validation of simulation results. Classical twisted tape (CTT) with different twist ratios (y = 2.93, 3.91, 4.89) were also studied for comparison. The results show that the enhancement of heat transfer rate induced by the classical and V-cut twisted tape inserts increases with the Reynolds number and decreases with twist ratio. The results also revealed that the V-cut twisted tape with twist ratio y = 2.93 and cut depth w = 0.5 cm offered higher heat transfer rate with significant increases in friction factor than other tapes. In addition the results of V-cut twist tape compared with experimental and simulated data of right-left helical tape inserts (RLT), it is found that the V-cut twist tape offered better thermal contact between the surface and the fluid which ultimately leads to a high heat transfer coefficient. Consequently, 107% of maximum heat transfer was obtained by using this configuration.
  4. Al-Amiery AA, Kadhum AA, Obayes HR, Mohamad AB
    Bioinorg Chem Appl, 2013;2013:354982.
    PMID: 24170994 DOI: 10.1155/2013/354982
    The novel curcumin derivative (1E,4Z,6E)-5-chloro-1,7-bis(4-hydroxy-3-methoxyphenyl)hepta-1,4,6-trien-3-one (5-chlorocurcumin) was prepared from natural curcumin. The newly synthesised compound was characterised by spectral studies (IR, 1H NMR, and 13C NMR). The free radical scavenging activity of 5-chlorocurcumin has been determined by measuring interaction with the stable free radical DPPH, and 5-chlorocurcumin has shown encouraging antioxidant activities. Theory calculations of the synthesised 5-chlorocurcumin were performed using molecular structures with optimised geometries. Molecular orbital calculations provided a detailed description of the orbitals, including spatial characteristics, nodal patterns, and the contributions of individual atoms.
  5. Al-Amiery AA, Kadhum AA, Mohamad AB
    Bioinorg Chem Appl, 2012;2012:795812.
    PMID: 22400016 DOI: 10.1155/2012/795812
    Metal complexes of (Z)-2-(pyrrolidin-2-ylidene)hydrazinecarbothioamide (L) with Cu(II), Co(II), and Ni(II) chlorides were tested against selected types of fungi and were found to have significant antifungal activities. The free-radical-scavenging ability of the metal complexes was determined by their interaction with the stable free radical 2,2''-diphenyl-1-picrylhydrazyl, and all the compounds showed encouraging antioxidant activities. DFT calculations of the Cu complex were performed using molecular structures with optimized geometries. Molecular orbital calculations provide a detailed description of the orbitals, including spatial characteristics, nodal patterns, and the contributions of individual atoms.
  6. Kadhum AA, Al-Amiery AA, Musa AY, Mohamad AB
    Int J Mol Sci, 2011;12(9):5747-61.
    PMID: 22016624 DOI: 10.3390/ijms12095747
    The antioxidant activity of two synthesized coumarins namely, N-(4,7-dioxo-2- phenyl-1,3-oxazepin-3(2H,4H,7H)-yl)-2-(2-oxo-2H-chromen-4-yloxy)acetamide 5 and N-(4-oxo-2-phenylthiazolidin-3-yl)-2-(2-oxo-2H-chromen-4-yloxy)acetamide 6 were studied with the DPPH, hydrogen peroxide and nitric oxide radical methods and compared with the known antioxidant ascorbic acid. Compounds 5 and 6 were synthesized in a good yield from the addition reaction of maleic anhydride or mercaptoacetic acid to compound 4, namely N'-benzylidene-2-(2-oxo-2H-chromen-4-yloxy)acetohydrazide. Compound 4 was synthesized by the condensation of compound 3, namely 2-(2-oxo-2H-chromen-4-yloxy) acetohydrazide, with benzaldehyde. Compound 3, however, was synthesized from the addition of hydrazine to compound 2, namely ethyl 2-(2-oxo-2H-chromen-4-yloxy)acetate, which was synthesized from the reaction of ethyl bromoacetate with 4-hydroxycoumarin 1. Structures for the synthesized coumarins 2-6 are proposed on the basis of spectroscopic evidence.
  7. Al-Amiery AA, Musa AY, Kadhum AA, Mohamad AB
    Molecules, 2011 Aug 10;16(8):6833-43.
    PMID: 21832973 DOI: 10.3390/molecules16086833
    New coumarin derivatives, namely 7-[(5-amino-1,3,4-thiadiazol-2-yl)methoxy]-2H-chromen-2-one, 5-[(2-oxo-2H-chromen-7-yloxy)methyl]-1,3,4-thiadiazol-2(3H)-one, 2-[2-(2-oxo-2H-chromen-7-yloxy)acetyl]-N-phenylhydrazinecarbothioamide, 7-[(5-(phenylamino)-1,3,4-thiadiazol-2-yl)methoxy]-2H-chromen-2-one and 7-[(5-mercapto-4-phenyl-4H-1,2,4-triazol-3-yl)methoxy]-2H-chromen-2-one were prepared starting from the natural compound umbelliferone. The newly synthesized compounds were characterized by elemental analysis and spectral studies (IR, ¹H-NMR and ¹³C-NMR).
  8. Kadhum AA, Mohamad AB, Al-Amiery AA, Takriff MS
    Molecules, 2011 Aug 15;16(8):6969-84.
    PMID: 21844844 DOI: 10.3390/molecules16086969
    3-Aminocoumarin (L) has been synthesized and used as a ligand for the formation of Cr(III), Ni(II), and Cu(II) complexes. The chemical structures were characterized using different spectroscopic methods. The elemental analyses revealed that the complexes where M=Ni(II) and Cu(II) have the general formulae [ML(2)Cl(2)], while the Cr(III) complex has the formula [CrL(2)Cl(2)]Cl. The molar conductance data reveal that all the metal chelates, except the Cr(III) one, are non-electrolytes. From the magnetic and UV-Visible spectra, it is found that these complexes have octahedral structures. The stability for the prepared complexes was studied theoretically using Density Function Theory. The total energy for the complexes was calculated and it was shown that the copper complex is the most stable one. Complexes were tested against selected types of microbial organisms and showed significant activities. The free radical scavenging activity of metal complexes have been determined by measuring their interaction with the stable free radical DPPH and all the compounds have shown encouraging antioxidant activities.
  9. Mohammed IA, Sankar G, Khairuddean M, Mohamad AB
    Molecules, 2010 Apr 30;15(5):3260-9.
    PMID: 20657475 DOI: 10.3390/molecules15053260
    A series of new mesogenic azomethine diols were successfully synthesized by condensation reactions between various chloroalkanols and N,N'-bis(4-hydroxy)-benzylidene-o-toluidine (1). The structures of these compounds were confirmed by CHN, FT-IR, (1)H-NMR, and (13)C-NMR spectrophotometer. Their thermotropic liquid crystalline behavior was studied using differential scanning calorimetry (DSC) and polarizing optical microscope (POM). 4,4'-di(4-Hydroxybutoxy)-N-benzylidine-o-tolidine (2a) does not exhibit liquid crystalline properties. A nematic texture was observed for mesogenic diols 2b, and 2d, whereas the diol 2c exhibits a smectic mesophase. The increase of terminal alkyl chain in these mesogenic diols leads to a decrease in the transition temperature.
  10. Myint S, Daud WR, Mohamad AB, Kadhum AA
    J Chromatogr B Biomed Appl, 1996 Apr 26;679(1-2):193-5.
    PMID: 8998560
    An ethanolic extract of cloves was analyzed by gas chromatography directly to identify eugenol and other major phenolic compounds without previous separation of other components. Separation was performed on a fused-silica capillary column of 30 m x 0.53 mm I.D., 0.53 microns film thickness. The detector was a flame ionization detector. Helium gas at a flow-rate of 3 ml/min was used as a carrier gas. The analysis were performed with linear temperature programming. Nine components were detected and special attention was given to the major phenolic compound, eugenol.
  11. Alamiery A, Mohamad AB, Kadhum AAH, Takriff MS
    Data Brief, 2022 Feb;40:107838.
    PMID: 35106341 DOI: 10.1016/j.dib.2022.107838
    This data article includes data described in the investigation report entitled "The synergistic role of azomethine group and triazole ring at improving the anti-corrosive performance of 2-amino-4-phenylthiazole" (Alamiery et al., 2021). In this data article, a comprehensive effect of 2-Amino-4-phenyl-N-benzylidene-5-(1,2,4-triazol-1-yl)thiazole (APNT) and 2-amino-4-phenylthiazole (APT) and optimized process parameter of the inhibitor in 1 M HCl solution was presented using gravimetric techniques and Density functional theory. The presence of the inhibitors influenced the corrosion resistance of mild steel (MS). Inhibition efficiencies values of 98.1% and 94.74% were recorded as results of inhibition of the MS by the inhibiting compounds APNT and ATP respectively. DFT studies observed that the presence of benzylidene to the APNT and the substitution of a triazole in the thiazole ring are adsorption sites that increase the interaction of the APNT molecules with the iron atoms on the MS surface.
  12. Al-Amiery AA, Kadhum AAH, Mohamad AB, Junaedi S
    Materials (Basel), 2013 Apr 02;6(4):1420-1431.
    PMID: 28809218 DOI: 10.3390/ma6041420
    2-(1-methyl-4-((E)-(2-methylbenzylidene)amino)-2-phenyl-1H-pyrazol-3(2H)-ylidene)-hydrazineecarbothioamide (HCB) was synthesized as a corrosion inhibitor from the reaction of 4-aminoantipyrine, thiosemicarbazide and 2-methylbenzaldehyde. The corrosion inhibitory effects of HCB on mild steel in 1.0 M HCl were investigated using potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS). The results showed that HCB inhibited mild steel corrosion in acidic solution and inhibition efficiency increased with an increase in the concentration of the inhibitor. The inhibition efficiency was up to 96.5% at 5.0 mM. Changes in the impedance parameters suggested that HCB adsorbed on the surface of mild steel, leading to the formation of a protective film. The novel corrosion inhibitor synthesized in the present study was characterized using Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR) spectral data.
  13. Al-Amiery AA, Kadhum AA, Mohamad AB
    Molecules, 2012 May 14;17(5):5713-23.
    PMID: 22628043 DOI: 10.3390/molecules17055713
    Newly synthesized coumarins 4-((5-mercapto-4-phenyl-4H-1,2,4-triazol-3-yl)-methoxy)-2H-chromen-2-one and 4-((5-(phenylamino)-1,3,4-thiadiazol-2-yl)-methoxy)-2H-chromen-2-one were tested against selected types of fungi and showed significant activities. DFT calculations of the synthesized coumarins were performed using molecular structures with optimized geometries. Molecular orbital calculations provide a detailed description of the orbitals, including spatial characteristics, nodal patterns, and the contributions of individual atoms.
  14. Al-Majedy YK, Al-Amiery AA, Kadhum AA, Mohamad AB
    PLoS One, 2016;11(5):e0156625.
    PMID: 27243231 DOI: 10.1371/journal.pone.0156625
    The synthesis of derivatives of 4-Methylumbelliferone (4-MUs), which are structurally interesting antioxidants, was performed in this study. The modification of 4-Methylumbelliferone (4-MU) by different reaction steps was performed to yield the target compounds, the 4-MUs. The 4-MUs were characterized by different spectroscopic techniques (Fourier transform infrared; FT-IR and Nuclear magnetic resonance; NMR) and micro-elemental analysis (CHNS). The in vitro antioxidant activity of the 4-MUs was evaluated in terms of their free radical scavenging activities against 2,2-diphenyl-1-picrylhydrazyl (DPPH), Nitric oxide radical scavenging activity assay, chelating activity and their (FRAP) ferric-reducing antioxidant power, which were compared with a standard antioxidant. Our results reveal that the 4-MUs exhibit excellent radical scavenging activities. The antioxidant mechanisms of the 4-MUs were also studied. Density Function Theory (DFT)-based quantum chemical studies were performed with the basis set at 3-21G. Molecular models of the synthesized compounds were studied to understand the antioxidant activity. The electron levels, namely HOMO (highest occupied molecular orbital) and LUMO (lowest unoccupied molecular orbital), for these synthesized antioxidants were also studied.
  15. Gaaz TS, Sulong AB, Akhtar MN, Kadhum AA, Mohamad AB, Al-Amiery AA
    Molecules, 2015;20(12):22833-47.
    PMID: 26703542 DOI: 10.3390/molecules201219884
    The aim of this review was to analyze/investigate the synthesis, properties, and applications of polyvinyl alcohol-halloysite nanotubes (PVA-HNT), and their nanocomposites. Different polymers with versatile properties are attractive because of their introduction and potential uses in many fields. Synthetic polymers, such as PVA, natural polymers like alginate, starch, chitosan, or any material with these components have prominent status as important and degradable materials with biocompatibility properties. These materials have been developed in the 1980s and are remarkable because of their recyclability and consideration of the natural continuation of their physical and chemical properties. The fabrication of PVA-HNT nanocomposites can be a potential way to address some of PVA's limitations. Such nanocomposites have excellent mechanical properties and thermal stability. PVA-HNT nanocomposites have been reported earlier, but without proper HNT individualization and PVA modifications. The properties of PVA-HNT for medicinal and biomedical use are attracting an increasing amount of attention for medical applications, such as wound dressings, drug delivery, targeted-tissue transportation systems, and soft biomaterial implants. The demand for alternative polymeric medical devices has also increased substantially around the world. This paper reviews individualized HNT addition along with crosslinking of PVA for various biomedical applications that have been previously reported in literature, thereby showing the attainability, modification of characteristics, and goals underlying the blending process with PVA.
  16. Al-Amiery AA, Al-Majedy YK, Kadhum AA, Mohamad AB
    Molecules, 2014 Dec 29;20(1):366-83.
    PMID: 25551187 DOI: 10.3390/molecules20010366
    The anticorrosion ability of a synthesized coumarin, namely 2-(coumarin-4-yloxy)acetohydrazide (EFCI), for mild steel (MS) in 1 M hydrochloric acid solution has been studied using a weight loss method. The effect of temperature on the corrosion rate was investigated, and some thermodynamic parameters were calculated. The results indicated that inhibition efficiencies were enhanced with an increase in concentration of inhibitor and decreased with a rise in temperature. The IE value reaches 94.7% at the highest used concentration of the new eco-friendly inhibitor. The adsorption of inhibitor on MS surface was found to obey a Langmuir adsorption isotherm. Scanning electron microscopy (SEM) was performed on inhibited and uninhibited mild steel samples to characterize the surface. The Density Function theory (DFT) was employed for quantum-chemical calculations such as EHOMO (highest occupied molecular orbital energy), ELUMO (lowest unoccupied molecular orbital energy) and μ (dipole moment), and the obtained results were found to be consistent with the experimental findings. The synthesized inhibitor was characterized by Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopic studies.
  17. Al-Alwani MA, Mohamad AB, Kadhum AA, Ludin NA
    PMID: 25483560 DOI: 10.1016/j.saa.2014.11.018
    Nine solvents, namely, n-hexane, ethanol, acetonitrile, chloroform, ethyl-ether, ethyl-acetate, petroleum ether, n-butyl alcohol, and methanol were used to extract natural dyes from Cordyline fruticosa, Pandannus amaryllifolius and Hylocereus polyrhizus. To improve the adsorption of dyes onto the TiO2 particles, betalain and chlorophyll dyes were mixed with methanol or ethanol and water at various ratios. The adsorption of the dyes mixed with titanium dioxide (TiO2) was also observed. The highest adsorption of the C.fruticosa dye mixed with TiO2 was achieved at ratio 3:1 of methanol: water. The highest adsorption of P.amaryllifolius dye mixed with TiO2 was observed at 2:1 of ethanol: water. H.polyrhizus dye extracted by water and mixed with TiO2 demonstrated the highest adsorption among the solvents. All extracted dye was adsorbed onto the surface of TiO2 based on Fourier Transform Infrared Spectroscopy (FTIR) analysis. The inhibition of crystallinity of TiO2 was likewise investigated by X-ray analysis. The morphological properties and composition of dyes were analyzed via SEM and EDX.
  18. Hussein HT, Kadhim A, Al-Amiery AA, Kadhum AA, Mohamad AB
    ScientificWorldJournal, 2014;2014:842062.
    PMID: 25136694 DOI: 10.1155/2014/842062
    Influence of laser treatment on mechanical properties, wear resistance, and Vickers hardness of aluminum alloy was studied. The specimens were treated by using Nd:YaG laser of energy 780 mj, wavelength 512 nm, and duration time 8 ns. The wear behavior of the specimens was studied for all specimens before and after treatment by Nd:YaG laser and the dry wear experiments were carried out by sing pinon-disc technique. The specimens were machined as a disk with diameter of 25 mm and circular groove in depth of 3 mm. All specimens were conducted by scanning electron microscopy (SEM), energy-dispersive X-ray fluorescence analysis (EDS), optical microscopy, and Vickers hardness. The results showed that the dry wear rate was decreased after laser hardening and increased Vickers hardness values by ratio of 2.4:1. The results showed that the values of wear rate for samples having circular grooves are less than samples without grooves after laser treatment.
  19. Al-Majedy YK, Kadhum AA, Al-Amiery AA, Mohamad AB
    Molecules, 2014 Aug 07;19(8):11791-9.
    PMID: 25105917 DOI: 10.3390/molecules190811791
    Some novel coumarins were synthesized starting from 4-hydroxycoumarin and methyl bromoacetate. The structures of the newly obtained compounds were confirmed by elemental analysis, mass, IR and NMR spectra.
  20. Kadhim A, Salim ET, Fayadh SM, Al-Amiery AA, Kadhum AA, Mohamad AB
    ScientificWorldJournal, 2014;2014:490951.
    PMID: 24737973 DOI: 10.1155/2014/490951
    Laser shock processing (LSP) is an innovative surface treatment technique with high peak power, short pulse, and cold hardening for strengthening metal materials. LSP is based on the application of a high intensity pulsed laser beam (I > 1 GW/cm(2); t < 50 ns) at the interface between the metallic target and the surrounding medium (a transparent confining material, normally water) forcing a sudden vaporization of the metallic surface into a high temperature and density plasma that immediately develops inducing a shock wave propagating into the material. The shock wave induces plastic deformation and a residual stress distribution in the target material. In this paper we study the increase of microhardness and surface roughness with the increase of laser pulse energy in 2024-T3 Al alloy. The influence of the thickness of the confining layer (water) on microhardness and surface roughness is also studied. In addition, the effect of LSP treatment with best conditions on wear behaviors of the alloy was investigated.
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