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  1. Fulltext Polymerization and Applications of Poly(methyl methacrylate)-Graphene Oxide Nanocomposites: A Review
    Ahamad Said MN, Hasbullah NA, Rosdi MRH, Musa MS, Rusli A, Ariffin A, et al.
    ACS Omega, 2022 Dec 27;7(51):47490-47503.
    PMID: 36591191 DOI: 10.1021/acsomega.2c04483
    Graphene oxide (GO)-incorporated poly(methyl methacrylate) (PMMA) nanocomposites (PMMA-GO) have demonstrated a wide range of outstanding mechanical, electrical, and physical characteristics. It is of interest to review the synthesis of PMMA-GO nanocomposites and their applications as multifunctional structural materials. The attention of this review is to focus on the radical polymerization techniques, mainly bulk and emulsion polymerization, to prepare PMMA-GO polymeric nanocomposite materials. This review also discusses the effect of solvent polarity on the polymerization process and the types of surfactants (anionic, cationic, nonionic) and initiator used in the polymerization. PMMA-GO nanocomposite synthesis using radical polymerization-based techniques is an active topic of study with several prospects for considerable future improvement and a variety of possible emerging applications. The concentration and dispersity of GO used in the polymerization play critical roles to ensure the functionality and performance of the PMMA-GO nanocomposites.
  2. PASS-assisted design, synthesis and antioxidant evaluation of new butylated hydroxytoluene derivatives
    Ariffin A, Rahman NA, Yehye WA, Alhadi AA, Kadir FA
    Eur J Med Chem, 2014 Nov 24;87:564-77.
    PMID: 25299680 DOI: 10.1016/j.ejmech.2014.10.001
    New multipotent antioxidants (MPAOs), namely 1,3,4-thiadiazoles and 1,2,4-triazoles bearing the well-known free radical scavenger butylated hydroxytoluene (BHT), were designed and synthesized using an acid-(base-) catalyzed intramolecular dehydrative cyclization reaction of the corresponding 1-acylthiosemicarbazides. The structure-activity relationship (SAR) of the designed antioxidants was performed along with the prediction of activity spectra for substances (PASS) training set. Experimental studies based on antioxidant activity using DPPH and lipid peroxidation assays verified the predictions obtained by the PASS-assisted design strategy. Compounds 4a-b, 5a-b and 6a-b showed an inhibition of stable DPPH free radicals at a 10(-4) M more than the well-known standard antioxidant BHT. Compounds with p-methoxy substituents (4b, 5b and 6b) were more active than o-methoxy substituents (4a, 5a and 6a). With an IC50 of 2.85 ± 1.09 μM, compound 6b exhibited the most promising in vitro inhibition of lipid peroxidation, inhibiting Fe(2+)-induced lipid peroxidation of essential oils derived from the egg yolk-based lipid-rich medium by 86.4%. The parameters for the drug-likeness of these BHT derivatives were also evaluated according to Lipinski's 'rule-of-five'. All of the BHT derivatives were found to violate one of Lipinski's parameters (Log P ≥ 5) even though they have been found to be soluble in protic solvents. The predictive TPSA and %ABS data allow for the conclusion that these compounds could have a good capacity for penetrating cell membranes. Therefore, these novel MPAOs containing lipophilic and hydrophilic groups can be proposed as potential antioxidants for tackling oxidative stress and lipid peroxidation processes.
  3. Acute pancreatitis: is early CT necessary?
    Ariffin AC, Ngadiron H
    Eur J Trauma Emerg Surg, 2017 12;43(6):883-884.
    PMID: 28936579 DOI: 10.1007/s00068-017-0843-1
  4. Verifying measurements of residual calcium content in demineralised cortical bone
    Ariffin AF, Yusof N, Mohd S, Rahman SA, Ramalingam S, Mansor A, et al.
    Cell Tissue Bank, 2019 Dec;20(4):527-534.
    PMID: 31456097 DOI: 10.1007/s10561-019-09785-4
    Calcium contents of demineralised human cortical bone determined by titrimetric assay and atomic absorption spectrophotometry technique were verified by comparing to neutron activation analysis which has high recovery of more than 90%. Conversion factors determined from the comparison is necessary to correct the calcium content for each technique. Femurs from cadaveric donors were cut into cortical rings and demineralised in 0.5 M hydrochloric acid for varying immersion times. Initial calcium content in the cortical bone measured by titration was 4.57%, only 21% of the measurement by neutron activation analysis; while measured by atomic absorption spectrophotometer was 13.4%, only 61% of neutron activation analysis. By comparing more readings with the measurements by neutron activation analysis with 93% recovery, a conversion factor of 4.83 was verified and applied for the readings by titration and 1.45 for atomic absorption spectrophotometer in calculating the correct calcium contents. The residual calcium content started to reduce after the cortical bone was demineralised in hydrochloric acid for 8 h and reduced to 13% after 24 h. Using the linear relationship, the residual calcium content could be reduced to less than 8% after immersion in hydrochloric acid for 40 h. Atomic absorption spectrophotometry technique is the method of choice for calcium content determination as it is more reliable compared to titrimetric assay.
  5. Fulltext Kinetic resolution of complexity of reaction paths in the alkaline hydrolysis of N-(2’-Hydroxyphenyl) phthalimide in mixed H2O-CH3CN solvent
    Ariffin, A., Khan, M.N., Sim, Y.L.
    ASM Science Journal, 2008;2(1):83-92.
    MyJurnal
    The rate of aqueous cleavage of N-(2’-hydroxyphenyl)phthalimide (A), monitored at 320 nm, 1.0  10–3 M NaOH, 35ºC and within CH3CN content range 1% – 80% v/v in mixed aqueous solvents, follows the reaction scheme: A + HO-/H2O ➝ B + HO-/H2O ➝ P1 + P2 where B, P1 and P2 represent N-(2’-hydroxyphenyl)phthalamic acid, phthalic acid and 2-hydroxyaniline, respectively. The values of k1 and k2 at different content of CH3CN have been calculated from a kinetic equation based upon a reaction scheme with two irreversible pseudo-first-order consecutive reaction paths. The values of k1/k2 are > 104 within CH3CN content range 1% – 80% v/v in mixed aqueous solvents. The intermediate hydrolysis product (B) exists in 72% dianionic, 27.9% monoanionic and 0.1% nonionic form under the present experimental conditions. Both dianionic and monoanionic forms of B are non-reactive while the nonionic form of B is reactive towards hydrolysis under such conditions.
  6. Activation of Intrinsic Apoptosis and G1 Cell Cycle Arrest by a Triazole Precursor, N-(4-chlorophenyl)-2-(4-(3,4,5-trimethoxybenzyloxy)benzoyl)-hydrazinecarbothioamide in Breast Cancer Cell Line
    Arulnathan SB, Leong KH, Ariffin A, Kareem HS, Cheah KKH
    Anticancer Agents Med Chem, 2020;20(9):1072-1086.
    PMID: 32188392 DOI: 10.2174/1871520620666200318100051
    BACKGROUND: Oxadiazoles, triazoles, and their respective precursors have been shown to exhibit various pharmacological properties, namely antitumour activities. Cytotoxic activity was reported for these compounds in various cancer cell lines.

    AIM AND OBJECTIVES: In this study, we aim at investigating the mechanism of apoptosis by N-(4-chlorophenyl)-2-(4- (3,4,5-trimethoxybenzyloxy)benzoyl)-hydrazinecarbothioamide, a triazole precursor, henceforth termed compound P7a, in breast cancer cell line, MCF-7. We first screen a series of analogues containing (3,4,5-trimethoxybenzyloxy) phenyl moiety in breast cancer cell lines (MCF-7 and MDA-MB-231) to select the most cytotoxic compound and demonstrate a dose- and time-dependent cytotoxicity. Then, we unravel the mechanism of apoptosis of P7a in MCF-7 as well as its ability to cause cell cycle arrest.

    METHODS: Synthesis was performed as previously described by Kareem and co-workers. Cytotoxicity of analogues containing (3,4,5-trimethoxybenzyloxy)phenyl moiety against MCF-7 and MDA-MB-231 cell lines was evaluated using the MTS assay. Flow cytometric analyses was done using Annexin V/PI staining, JC-1 staining and ROS assay. The activity of caspases using a chemoluminescence assay and western blot analysis was conducted to study the apoptotic pathway induced by the compound in MCF-7 cells. Lastly, cell cycle analysis was conducted using flow cytometry.

    RESULTS: Upon 48 hours of treatment, compound P7a inhibited the proliferation of human breast cancer cells with IC50 values of 178.92 ± 12.51μM and 33.75 ± 1.20μM for MDA-MB-231 and MCF-7, respectively. Additionally, compound P7a showed selectivity towards the cancer cell line, MCF-7 compared to the normal breast cell line, hTERT-HME1, an advantage against current anticancer drugs (tamoxifen and vinblastine). Flow cytometric analyses using different assays indicated that compound P7a significantly increased the proportion of apoptotic cells, increased mitochondria membrane permeabilisation and caused generation of ROS in MCF-7. In addition, cell cycle analysis showed that cell proliferation was arrested at the G1 phase in the MCF-7 cell line. Furthermore, upon treatment, the MCF-7 cell line showed increased activity of caspase-3/7, and caspase-9. Lastly, the western blot analysis showed the up-regulation of pro-apoptotic proteins along with up-regulation of caspase-7 and caspase-9, indicating that an intrinsic pathway of apoptosis was induced.

    CONCLUSION: The results suggest that compound P7a could be a potential chemotherapeutic agent for breast cancer.

  7. Fulltext The HUKM Spinal Instrumentation System for adolescent idiopathic scoliosis. A biomechanical comparison study using finite element analysis
    Azlan AM, Mohammad AR, Ariffin AK
    Med J Malaysia, 2005 Jul;60 Suppl C:30-4.
    PMID: 16381280 MyJurnal
    This finite element analysis is aimed at comparing relative stiffness of three different posterior instrumentation constructs: the Hospital Universiti Kebangsaan Malaysia Spinal Instrumentation System (HUKM-SIS), the Cotrell-Dubousset Instrumentation (CDI) and Harrington Instrumentation System (HIS), used in the treatment of adolescent idiopathic scoliosis (AIS). The constructs were tested under various loads using MSC Patran 2001 r2a. Under increasing flexion loads, there was a linearly corresponding increase in deflection magnitudes for all constructs on the load-deflection curve. The CDI was the stiffest construct under axial, forward flexion and extension loads, followed by the HUKM-SIS and HIS. Under lateral bending loads, the HUKM-SIS construct was the stiffest followed by CDI and HIS. The HUKM-SIS construct was stiffer than HIS under torsional loads. We conclude that multiple pedicle screws increase the stiffness of posterior instrumentation constructs under all loads and inter-segmental spinous processes wiring increase the stiffness against lateral bending.
  8. Fulltext Counting in the dark: non-intrusive laser scanning for population counting and identifying roosting bats
    Azmy SN, Sah SA, Shafie NJ, Ariffin A, Majid Z, Ismail MN, et al.
    Sci Rep, 2012;2:524.
    PMID: 22826802 DOI: 10.1038/srep00524
    Population surveys and species recognition for roosting bats are either based on capture, sight or optical-mechanical count methods. However, these methods are intrusive, are tedious and, at best, provide only statistical estimations. Here, we demonstrated the successful use of a terrestrial Light Detection and Ranging (LIDAR) laser scanner for remotely identifying and determining the exact population of roosting bats in caves. LIDAR accurately captured the 3D features of the roosting bats and their spatial distribution patterns in minimal light. The high-resolution model of the cave enabled an exact count of the visibly differentiated Hipposideros larvatus and their roosting pattern within the 3D topology of the cave. We anticipate that the development of LIDAR will open up new research possibilities by allowing researchers to study roosting behaviour within the topographical context of a cave's internal surface, thus facilitating rigorous quantitative characterisations of cave roosting behaviour.
  9. Radioluminescence sensing of radiology exposures using P-doped silica optical fibres
    Bradley DA, Zubair HT, Oresegun A, Louay GT, Ariffin A, Khandaker MU, et al.
    Appl Radiat Isot, 2018 Nov;141:176-181.
    PMID: 29673719 DOI: 10.1016/j.apradiso.2018.02.025
    In previous work we investigated the real-time radioluminescence (RL) yield of Ge-doped silica fibres and Al2O3 nanodot media, sensing electron- and x-ray energies and intensities at values familiarly obtained in external beam radiotherapy. The observation of an appreciable low-dose sensitivity has given rise to the realisation that there is strong potential for use of RL dosimetry in diagnostic radiology. Herein use has been made of P-doped silica optical fibre, 2 mm diameter, also including a 271 µm cylindrical doped core. With developing needs for versatile x-ray imaging dosimetry, preliminary investigations have been made covering the range of diagnostic x-ray tube potentials 30 kVp to 120 kVp, demonstrating linearity of RL with kVp as well as in terms of the current-time (mAs) product. RL yields also accord with the inverse-square law. Given typical radiographic-examination exposure durations from tens- to a few hundred milliseconds, particular value is found in the ability to record the influence of x-ray generator performance on the growth and decay of beam intensity, from initiation to termination.
  10. Fulltext Unrelated cord blood transplantation in children--a 10-year experience from UMMC
    Chan LL, Lin HP, Chong LA, Hany A, Ariffin AW
    Med J Malaysia, 2009 Jun;64(2):124-9.
    PMID: 20058571
    Children who would benefit from a haematopoietic stem cell transplantation often lacked a compatible sibling donor. Unrelated cord blood transplantation was offered as an alternative donor source for patients with a variety of malignant and non-malignant diseases who had no further treatment options. Cord blood units were sourced from various international cord blood registries. The median nucleated and CD34+ cell doses were 8.7 x 10(7)/kg and 2.6 x 10(5)/kg respectively. In spite of adequate cell doses, a high rate of non-engraftment of 32% was observed. Acute graft-versus-host disease (GVHD) occurred in 14 out of the 15 patients who engrafted with 53% being grade III to IV GVHD. The five year disease free survival was 40.7% with infection and GVHD being the commonest causes of death. The five year disease free survival was 20.5% and 60.7% for malignant and non-malignant diseases respectively.
  11. Activation of death receptor, DR5 and mitochondria-mediated apoptosis by a 3,4,5-trimethoxybenzyloxy derivative in wild-type and p53 mutant colorectal cancer cell lines
    Chan ZCK, Leong KH, Kareem HS, Norazit A, Noor SM, Ariffin A
    Naunyn Schmiedebergs Arch Pharmacol, 2020 03;393(3):405-417.
    PMID: 31641820 DOI: 10.1007/s00210-019-01730-2
    The rationale of designing compounds containing a (3,4,5-trimethoxybenzyloxy) phenyl moiety is largely due to its potential antioxidant and cytotoxic activities. A previous study focused on its antioxidant mechanism, whereas in this study, we investigated the cytotoxicity of a series of 28 analogues and the mechanism of apoptosis of the most cytotoxic compound against wild-type (HCT-116) and p53 mutant (HT-29) colorectal cancer cell lines. The series of analogues comprise of different families, namely hydrazone, oxadiazole, thiosemicarbazides and triazoles. In the initial cytotoxicity screening, N-(3,4,5-trimethoxybenzylidene)-4-(3,4,5-trimethoxybenzyloxy) benzohydrazide, henceforth known as, P5H, was found to be most cytotoxic against human colorectal cancer cell lines (IC50 for HCT-116 = 11.79 μM and HT-29 = 18.52 μM). Additionally, P5H was found to have some degree of selectivity towards cancer cells compared to normal human colon cells (CCD-112 CoN). Subsequent investigation had brought insight on P5H ability to induce apoptosis in both HCT-116 and HT-29 cell lines. Cell cycle analysis showed both cell lines were arrested at the G2/M phase upon treatment. Our study concluded that P5H induced the death receptor, DR5 in HCT-116 and mitochondria-mediated apoptosis pathway in HT-29. Therefore, P5H may be a promising candidate as a chemotherapy agent against colon cancer. Graphical abstract The apoptotic pathways induced in HT-29 and HCT-116 cells upon P5H treatment.
  12. Resveratrol analogue, (E)-N-(2-(4-methoxystyryl) phenyl) furan-2-carboxamide induces G2/M cell cycle arrest through the activation of p53-p21CIP1/WAF1 in human colorectal HCT116 cells
    Cheah FK, Leong KH, Thomas NF, Chin HK, Ariffin A, Awang K
    Apoptosis, 2018 Jun;23(5-6):329-342.
    PMID: 29754265 DOI: 10.1007/s10495-018-1457-8
    Resveratrol, a naturally occurring polyphenolic antioxidant, is a potential chemoprophylactic agent for various cancers, including colorectal cancer. Although emerging evidence continually suggests that a number of resveratrol derivatives may be better cancer chemopreventive candidates than resveratrol, studies on the mechanism of action of these derivatives are limited. This is the first study which investigates the mechanism underlying the cytotoxic effect of a synthesized resveratrol analogue, (E)-N-(2-(4-methoxystyryl) phenyl) furan-2-carboxamide (CS) on colorectal cancer. Previously, our group reported a series of synthesized resveratrol analogues, which showed cytotoxicity against a panel of cancer cell lines, in particular on colon cancer cells. In this study, we further discovered that CS also exerts a potent suppressive effect on HCT116 colorectal cancer cells. In contrast, normal colon cells (CCD-112 Con) were not sensitive to CS up to 72 h post treatment. CS caused cytotoxicity in HCT116 cells through several apoptotic events including activation of the Fas death receptor, FADD, caspase 8, caspase 3, caspase 9, and cleaved PARP, which occurred alongside cell cycle arrest from the up-regulation of p53 and p21. The results show that CS causes apoptosis via the activation of an extrinsic pathway leading to caspase activation and cell cycle arrest from activated p53. These findings suggest that CS may be a potential candidate for development as an anti-tumor agent in the future.
  13. Kinetic coupled with UV spectral evidence for near-irreversible nonionic micellar binding of N-benzylphthalimide under the typical reaction conditions: an observation against a major assumption of the pseudophase micellar model
    Cheong MY, Ariffin A, Khan MN
    J Phys Chem B, 2007 Oct 25;111(42):12185-94.
    PMID: 17914797
    Pseudo-first-order rate constants (k(obs)) for alkaline hydrolysis of N-benzylphthalimide (1) show a nonlinear decrease with the increase in [C(m)E(n)]T (total concentration of Brij 58, m = 16, n = 20 and Brij 56, m = 16, n = 10) at constant [CH(3)CN] and [NaOH]. These nonionic micellar effects, within the certain typical reaction conditions, have been explained in terms of the pseudophase micellar (PM) model. The values of micellar binding constants (KS) of 1 are 1.04 x 10(3) M(-1) (at 1.0 x 10(-3) M NaOH) and 1.08 x 10(3) M(-1) (at 2.0 x 10(-3) M NaOH) for C(16)E(20) as well as 600 M(-1) (at 7.6 x 10(-4) M NaOH) and 670 M(-1) (at 1.0 x 10(-3) M NaOH) for C(16)E(10) micelles. The pseudo-first-order rate constants (kM) for hydrolysis of 1 in C(16)E(20) micellar pseudophase are approximately 90-fold smaller than those (kW) in water phase. The values of kM for hydrolysis of 1 in C(16)E(10) micelles are almost zero. Kinetic coupled with UV spectral data reveals significant irreversible nonionic micellar binding of 1 molecules in the micellar environment of nearly zero hydroxide ion concentration at >or=0.14 M C(16)E(20) and 1.0 x 10(-3) M NaOH while such observations could not be detected at or=3 x 10(-3) M C(16)E(10) and 7.6 x 10(-4) M NaOH, while the rate of hydrolysis of 1 is completely ceased at >or=0.05 M C(16)E(10) and 7.6 x 10(-4) M NaOH. The rate of hydrolysis of 1 at 5.0 x 10(-2) and 8.8 x 10(-2) M C(16)E(10) and 1.0 x 10(-3) M NaOH reveals the formation of presumably phthalic anhydride, whereas such observation was not observed in the C(16)E(20) micellar system under similar experimental conditions.
  14. Fulltext Concordant childhood acute lymphoblastic leukemia in monozygotic twins
    Chin YM, Wan Ariffin A, Lin HP, Chan YS
    Med J Malaysia, 1996 Mar;51(1):145-8.
    PMID: 10967997
    Two 4-year-old monozygotic Chinese, female twins developed concordant childhood acute lymphoblastic leukemia (ALL) within an interval of about 2 weeks. Based on morphology and cytochemistry findings of the bone marrow blast cells, a diagnosis of ALL, L1 was made. Immunophenotyping showed the blast cells of both twins expressed similar antigens, i.e. HLA-DR, CD10, CD13, CD19, CD22 and CD34. Identical blood group, same HLA (human leucocyte antigen) genotype, sex and similar appearance suggest that the twins are monozygotic. Since the bone marrow leukemic cells of both twins were identical in morphology and expressed the same antigens with almost similar percentages of positivity, it is likely that the blast cells were derived from the same single clone. Based on the single clone hypothesis, the leukemogenic event must have arisen in utero in one twin and the cells from the abnormal clone then spread to the other twin via shared placental anastomoses.
  15. Kinetics and mechanism of the cleavage of phthalic anhydride in glacial acetic acid solvent containing aniline
    Damit EF, Ariffin A, Khan MN
    J Org Chem, 2008 Dec 5;73(23):9303-13.
    PMID: 18954113 DOI: 10.1021/jo8011072
    Apparent second-order rate constants (k(n)(app)) for the nucleophilic reaction of aniline (Ani) with phthalic anhydride (PAn) vary from 6.30 to 7.56 M(-1) s(-1) with the increase of temperature from 30 to 50 degrees C in pure glacial acetic acid (AcOH). However, the values of pseudo-first-order rate constants (k(s)) for the acetolysis of PAn in pure AcOH increase from 16.5 x 10(-4) to 10.7 x 10(-3) s(-1) with the increase of temperature from 30 to 50 degrees C. The values of k(n)(app) and k(s) vary from 5.84 to 7.56 M(-1) s(-1) and from 35.1 x 10(-4) to 12.4 x 10(-4) s(-1), respectively, with the increase of CH(3)CN content from 1% to 80% v/v in mixed AcOH solvents at 35 degrees C. The plot of k(s) versus CH(3)CN content shows a minimum (with 10(4) k(s) = 4.40 s(-1)) at 50% v/v CH(3)CN. Similarly, the variations of k(n)(app) and k(s) with the increasing content of tetrahydrofuran (THF) in mixed AcOH solvent reveal respective a maximum (with k(n)(app) = 17.5-15.6 M(-1) s(-1)) at 40-60% v/v THF and a minimum (with k(s) = approximately 0-1.2 x 10(-4) s (-1)) at 60-70% v/v THF. The respective values of DeltaH* and DeltaS* are 15.3 +/- 1.2 kcal mol(-1) and -20.1 +/- 3.8 cal K(-1) mol(-1) for k(s) and 1.1 +/- 0.5 kcal mol(-1) and -51.2 +/- 1.7 cal K(-1) mol(-1) for k(n)(app), while the values of k(n) (= k(n)(app)/f(b) with f(b) representing the fraction of free aniline base) are almost independent of temperature within the range 30-50 degrees C. A spectrophotometric approach has been described to determine f(b) in AcOH as well as mixed AcOH-CH(3)CN and AcOH-THF solvents. Thus, the observed data, obtained under different reaction conditions, have been explained quantitatively. An optimum reaction condition, within the domain of present reaction conditions, has been suggested for the maximum yield of the desired product, N-phenylphthalamic acid.
  16. Fulltext N-(2-Ethyl-phen-yl)phthalimide
    Fan YM, Zakaria N, Ariffin A, Ng SW
    Acta Crystallogr Sect E Struct Rep Online, 2008;64(Pt 9):o1699.
    PMID: 21201688 DOI: 10.1107/S1600536808020448
    In the title compound, C(16)H(13)NO(2), the phthalimide and benzene ring systems form a dihedral angle of 77.2 (1)°.
  17. Pro-apoptotic carboxamide analogues of natural fislatifolic acid targeting Mcl-1 and Bcl-2
    Gapil Tiamas S, Daressy F, Abou Samra A, Bignon J, Steinmetz V, Litaudon M, et al.
    Bioorg Med Chem Lett, 2020 04 01;30(7):127003.
    PMID: 32035700 DOI: 10.1016/j.bmcl.2020.127003
    A library of 26 novel carboxamides deriving from natural fislatifolic acid has been prepared. The synthetic strategy involved a bio-inspired Diels-Alder cycloaddition, followed by functionalisations of the carbonyl moiety. All the compounds were evaluated on Bcl-xL, Mcl-1 and Bcl-2 proteins. In this series of cyclohexenyl chalcone analogues, six compounds behaved as dual Bcl-xL/Mcl-1 inhibitors in micromolar range and one exhibited sub-micromolar affinities toward Mcl-1 and Bcl-2. The most potent compounds evaluated on A549 and MCF7 cancer cell lines showed moderate cytotoxicities.
  18. Fulltext Osteoblastic Cell Responses of Copper Nanoparticle Coatings on Ti-6Al-7Nb Alloy Using Electrophoretic Deposition Method
    Hameed HA, Hasan HA, Luddin N, Husein A, Ariffin A, Alam MK
    Biomed Res Int, 2022;2022:3675703.
    PMID: 35496039 DOI: 10.1155/2022/3675703
    AIM: To investigate and compare the cell cytotoxicity, proliferation, cell attachment, and morphology of human fetal osteoblasts (hFOB) cells of coated samples (titanium nanocopper (Ti Cu), titanium nanohydroxyapatite (Ti HA) and titanium nanocopper ion doped hydroxyapatite (Ti Cu/HA) and uncoated samples (Ti) in order to assess the suitability of these surface modifications on Ti-6Al-7Nb for dental implant application.

    MATERIALS AND METHODS: The cytotoxicity was studied by examining the hFOB cell response by MTT assessment. The cell morphology was evaluated by inverted microscopy and observed under scanning electronic microscopy (SEM).

    RESULTS: MTT assay results displayed that the Cu content on the surface of Ti-6Al-7Nb alloys did not produce any cytotoxic effect on cell viability. The cell viability rate in all samples ranges from 97% to 126%, indicating that hFOB cells grew at a high proliferation rate. However, no significant differences in cell viability were observed between Ti and Ti Cu and between Ti HA and Ti Cu/HA groups. Microscopic examination demonstrated no difference in the cell morphology of hFOB among all samples. In addition, SEM observation indicated favorable adhesion and spreading of the cells on the coated and uncoated samples.

    CONCLUSIONS: The surface modification of Ti-6Al-7Nb alloy with Cu, HA, and Cu/HA exhibits good cell biocompatibility, and the Cu has no influence on the cell proliferation and differentiation of hFOB.

  19. Remote Steric and Electronic Effects of N-Heterocyclic Carbene Ligands on Alkene Reactivity and Regioselectivity toward Hydrocupration Reactions: The Role of Expanded-Ring N-Heterocyclic Carbenes
    Hussein AA, Ariffin A
    J Org Chem, 2023 Sep 15;88(18):13009-13021.
    PMID: 37649423 DOI: 10.1021/acs.joc.3c01121
    The remote groups in N-heterocyclic carbene (NHC) ligands have a significant influence on metal-catalyzed reactions. We examine how remote bulkiness, electronic groups, and expanded-ring NHCs (ER-NHCs) influence alkene reactivity and regioselectivity toward hydrocupration using density functional theory calculations. The impact of remote steric bulkiness on the Cu-H insertion rate is analyzed, revealing a strong correlation between the steric substituent constant and rate ratio, where a bulky group increases the rate due to reduced steric effects in the transition state (TS). The steric properties of the examined catalysts (with a remote group R2 = CPh3, CHPh2, CH2Ph, CH3, and H) and their corresponding TSs are found to be modulated greatly by the remote steric substitution group and the ring size of the NHC ligand. Enhanced bulkiness enhances the nucleophilic Cu-H moiety. The remote electronic groups have a smaller impact on insertion barrier compared to that of steric hindrance. Furthermore, ER-NHC exploration indicates that NHCs with over five-membered rings have a significantly negative influence on the reaction rate. Finally, with a highly bulky group (R2 = CPh3), anti-Markovnikov insertion preference is attributed to high interaction energy and improved steric properties. Overall, our findings here provide valuable insights for the development of a more effective catalyst in metal-catalyzed reactions.
  20. Fulltext N-(3-Methyl-phen-yl)quinoxalin-2-amine monohydrate
    Idris A, Abdullah Z, Ariffin A, Fairuz ZA, Ng SW, Tiekink ER
    Acta Crystallogr Sect E Struct Rep Online, 2010;66(Pt 9):o2276.
    PMID: 21588631 DOI: 10.1107/S1600536810031260
    The quinoxaline system in the title hydrate, C(15)H(13)N(3)·H(2)O, is roughly planar, the r.m.s. deviation for the 18 non-H atoms being 0.188 Å; this conformation features a short intra-molecular C-H⋯N(pyrazine) inter-action. In the crystal, the amine H atom forms an N-H⋯O hydrogen bond to the water mol-ecule, which in turn forms two O-H⋯N hydrogen bonds to the pyrazine N atoms of different organic mol-ecules. These inter-actions lead to supra-molecular arrays in the bc plane that are two mol-ecules thick; additional π-π inter-actions stabilize the layers [ring centroid-centroid distance = 3.5923 (7) Å]. The layers stack along the a-axis direction via C-H⋯π contacts.
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