Displaying publications 41 - 60 of 103 in total

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  1. Hassan ND, Tajuddin HA, Abdullah Z, Ng SW
    PMID: 21201798 DOI: 10.1107/S1600536808026834
    The dihedral angle between the two aromatic ring systems in the title compound, C(15)H(12)N(2)O, is 42.6 (1)°. The angle at the O atom is widened to 117.7 (1)°.
  2. Hassan ND, Tajuddin HA, Abdullah Z, Ng SW
    PMID: 21201795 DOI: 10.1107/S1600536808026809
    The aromatic ring systems in the title compound, C(14)H(10)N(2)O, form a dihedral angle of 63.8 (1)°, resulting in an opening up of the ether-O atom angle to 118.2 (1)°.
  3. Fairuz MZ, Aiyub Z, Abdullah Z, Ng SW
    PMID: 21201779 DOI: 10.1107/S1600536808026317
    The two aromatic rings of each of the four independent molecules in the asymmetric unit of the title compound, C(11)H(9)ClN(2), are approximately coplanar; the four mol-ecules are arranged into two amino-pyridyl N-H⋯N hydrogen-bonded pairs. The structure has a 15% twin component related by a twofold rotation about [100].
  4. Hassan ND, Tajuddin HA, Abdullah Z, Ng SW
    PMID: 21201797 DOI: 10.1107/S1600536808026822
    The dihedral angle between the two aromatic ring systems in the title compound, C(15)H(12)N(2)O, is 79.4 (1)°. The angle at the O atom is widened to 116.93 (9)°.
  5. Hassan ND, Tajuddin HA, Abdullah Z, Ng SW
    PMID: 21201796 DOI: 10.1107/S1600536808026810
    The dihedral angle between the two aromatic ring systems in the title compound, C(15)H(12)N(2)O, is 85.9 (1)°; The angle at the O atom is widened to 118.2 (2)°. The quinoxalin-yloxy part of the mol-ecule lies on a mirror plane and the tolyl group is disordered over two positions about the mirror plane.
  6. Abdullah Z, Tahir NM, Abas MR, Aiyub Z, Low BK
    Molecules, 2004 Jun 30;9(7):520-6.
    PMID: 18007451
    The reactions of 2-chloropyrimidine with methylamine, ethylamine and piperidine gave the corresponding 2-N-methylamino-, 2-N-ethylamino- and 2N- piperidinopyrimidines, respectively. The fluorescence properties of these alkylamino derivatives in chloroform, ethyl acetate, carbon tetrachloride, acetone, ether, ethanol and methanol were studied. All the alkylamino derivatives showed the highest fluorescence intensity in polar protic solvents; thus 2-N-methylaminopyrimidine (highest fluorescence intensity at 377 nm when excited at 282 nm) and 2-N-ethylaminopyrimidine (highest fluorescence intensity at 375 nm, when excited at 286 nm) showed the highest fluorescence in methanol. In ethanol, 2-N-piperidinopyrimidine showed a fluorescence peak at 403 nm when excited at 360 nm and in chloroform it fluoresced at 392 nm when excited at 356 nm.
  7. Ismail IN, Asri NI, Tajuddin HA, Abdullah Z
    J Fluoresc, 2015 Jul;25(4):777-85.
    PMID: 26054802 DOI: 10.1007/s10895-015-1587-0
    A coumarin-terminated self-assembled monolayer on silver particles (C-SAM) from the reduction of silver ions in the presence of compound 3 was successfully prepared by utilizing phase transfer method, and analyzed by FTIR, SEM-EDS, UV-Visible and a particle sizer. The fluorescence behavior of coumarin termini was carried out in ethanol and chloroform with emission wavelength determined at 386 nm, suggesting an interaction between the carbonyl group and the solvent media. The dispersion was then investigated in acidic and basic conditions, showing a direct proportional correlation between the emission and the pH of the aqueous. These results were consistent for interpreting hydrogen bonds, particularly between the carbonyl group with either proton of the alcohol (C=O----H-O-R) or positive species in acidic conditions (C=O----H(+)). The interactions were possible only when the coumarin terminal rearranged in the monolayer and the carbonyl exerted towards the solvent media, while the rest of the molecules were separated from the solvents.
  8. Abdullah Z, Taip FS, Kamal SMM, Rahman RZA
    Foods, 2020 Aug 26;9(9).
    PMID: 32858797 DOI: 10.3390/foods9091177
    The moisture content of a powder is a parameter crucial to be controlled in order to produce stable products with a long shelf life. Inferential control is the best solution to control the moisture content due to difficulty in measuring this variable online. In this study, fundamental and empirical approaches were used in designing the nonlinear model-based inferential control of moisture content of coconut milk powder that was produced from co-current spray dryer. A one-dimensional model with integration of reaction engineering approach (REA) model was used to represent the dynamic of the spray drying process. The empirical approach, i.e., nonlinear autoregressive with exogenous input (NARX) and neural network, was used to allow fast and accurate prediction of output response in inferential control. Minimal offset (<0.0003 kg/kg) of the responses at various set points indicate high accuracy of the neural network estimator. The nonlinear model-based inferential control was able to provide stable control response at wider process operating conditions and acceptable disturbance rejection. Nevertheless, the performance of the controller depends on the tuning rules used.
  9. Abdo Qaid EY, Abdullah Z, Zakaria R, Long I
    Int J Mol Sci, 2022 Nov 03;23(21).
    PMID: 36362262 DOI: 10.3390/ijms232113474
    Neuroinflammation following lipopolysaccharide (LPS) administration induces locomotor deficits and anxiety-like behaviour. In this study, minocycline was compared to memantine, an NMDA receptor antagonist, for its effects on LPS-induced locomotor deficits and anxiety-like behaviour in rats. Adult male Sprague Dawley rats were administered either two different doses of minocycline (25 or 50 mg/kg/day, i.p.) or 10 mg/kg/day of memantine (i.p.) for 14 days four days prior to an LPS (5 mg/kg, i.p.) injection. Locomotor activity and anxiety-like behaviour were assessed using the open-field test (OFT). The phosphorylated tau protein level was measured using ELISA, while the expression and density of brain-derived neurotrophic factor (BDNF) and cAMP response element-binding (CREB) protein in the medial prefrontal cortex (mPFC) were measured using immunohistochemistry and Western blot, respectively. Minocycline treatment reduced locomotor deficits and anxiety-like behaviour associated with reduced phosphorylated tau protein levels, but it upregulated BDNF/CREB protein expressions in the mPFC in a comparable manner to memantine, with a higher dose of minocycline having better benefits. Minocycline treatment attenuated LPS-induced locomotor deficits and anxiety-like behaviour in rats and decreased phosphorylated tau protein levels, but it increased the expressions of the BDNF/CREB proteins in the mPFC.
  10. Abdullah Z, Putri KYS, Raza SH, Istiyanto SB
    BMC Public Health, 2022 Jan 14;22(1):99.
    PMID: 35031029 DOI: 10.1186/s12889-021-12480-3
    BACKGROUND: THE CONTEXT AND PURPOSE OF THE STUDY: Unhealthy food consumption has raised an alarming situation of obesity among Asian nations and posing serious threats to human health. Recent studies have acknowledged that organic food consumption has been contrariwise associated with obesity. The consumption of healthy food has received research attention in social marketing and several antecedents and consequences have been identified. However, to date, there is a void in literature that how social, individual, and marketing elements together tradeoff in predicting a healthy lifestyle. Thus, the current investigation unfolds the antecedents of healthy foods' adoption in Asia by integrating the brand signaling and theory of planned behavior.

    METHODS: The data of 241 respondents were collected from selected social media Facebook communities through a survey using assessed 42 questions. For this purpose, participants' Facebook accounts were selected from the online healthy communities such as 'Diet Suku Suku Separuh' (469,000 followers), 'Hiking, and Camping around Malaysia' (351,200 followers), and 'Healthy Malaysia' (332 followers). The enumerator also engaged with the online community by liking posts and following health accounts.

    RESULTS: The data was analyzed using PLS (SEM) approach, the outcomes of hypotheses revealed interesting information that health consciousness not significantly predicts the purchase intention of healthy food. All antecedents were significant contributors to the prediction of foods' purchase intentions in this study. However, the findings indicated that no positive relationship exists between brand image identifications and brand credibility identifications, and healthy foods' purchase intentions identifications. The findings also indicated that no positive relationship exists between health consciousness identifications and healthy foods' purchase intentions identifications. Owing to the perilous increase in obesity among the general public in Asia. This study reinforced the factor that can help in the adoption of a healthy lifestyle. The study validated that a healthy lifestyle is reliant on the consumers' health consciousness, environmental concern, and innovativeness through motivating the consumers' healthy foods' purchase intentions. Surprisingly, the results highlighted that respondents have not identified brand image and credibility as an antecedent of purchase intention. Given that organic food brands are somewhat new in Asian markets and therefore, brands must endure crisis marketing practices to improve their brand recognition. Therefore, policymakers must facilitate the food promotional activities that are critical to enhancing the perceived benefits of organic food to combat issues like obesity. This paper offers a foundation for future empirical investigations in Asia and various stakeholders on how to promote a healthy lifestyle in Asia. Specifically, the results will help policymakers to offer positive policies and procedures for the improvement of a healthy lifestyle through the understanding of the antecedents and consequences of health-conscious consumers' healthy foods' purchase intentions.

  11. Qaid EYA, Abdullah Z, Zakaria R, Long I
    Neurochem Res, 2023 May;48(5):1480-1490.
    PMID: 36509985 DOI: 10.1007/s11064-022-03842-3
    The oxidative stress-induced dysregulation of the cyclic AMP response element-binding protein- brain-derived neurotrophic factor (CREB-BDNF) cascade has been linked to cognitive impairment in several studies. This study aimed to investigate the effect of minocycline on the levels of oxidative stress markers, CREB, and BDNF in lipopolysaccharide (LPS)-induced cognitive impairment. Fifty adult male Sprague Dawley rats were divided randomly into five groups. Group 1 was an untreated control group. Groups 2, 3, 4 and 5 were treated concurrently with LPS (5 mg/kg, i.p) once on day 5 and normal saline (0.7 ml/rat, i.p) or minocycline (25 and 50 mg/kg, i.p) or memantine (10 mg/kg, i.p) once daily from day 1 until day 14, respectively. From day 15 to day 22 of the experiment, Morris Water Maze (MWM) was used to evaluate learning and reference memory in rats. The levels of protein carbonyl (PCO), malondialdehyde (MDA), catalase (CAT), and superoxide dismutase (SOD) were determined by enzyme-linked immunosorbent assay (ELISA). CREB and BDNF expression and density were measured by immunohistochemistry and western blot analysis, respectively. LPS administration significantly increased escape latency to the hidden platform with decreased travelled distance, swimming speed, target crossings and time spent in the target quadrant. Besides, the hippocampal tissue of LPS rats showed increased levels of PCO and MDA, decreased levels of CAT and SOD, and reduced expression and density of BDNF and CREB. Treatment with minocycline reversed these effects in a dose-dependent manner, comparable to the effects of memantine. Both doses of minocycline treatment protect against LPS-induced cognitive impairment by reducing oxidative stress and upregulating the CREB-BDNF signalling pathway in the rat hippocampus.
  12. Abdo Qaid EY, Abdullah Z, Zakaria R, Long I
    Neurol Res, 2024 Mar;46(3):261-271.
    PMID: 38122814 DOI: 10.1080/01616412.2023.2296754
    INTRODUCTION: The neuroinflammatory response was seen to impact the formation of phosphorylated tau protein in Alzheimer's disease (AD). This study aims to investigate the molecular mechanism of minocycline in reducing phosphorylated tau protein formation in the hippocampus of lipopolysaccharide (LPS)-induced rats.

    METHODS: Fifty adult male Sprague Dawley (SD) rats were randomly allocated to 1 of 5 groups: control, LPS (5 mg/kg), LPS + minocycline (25 mg/kg), LPS + minocycline (50 mg/kg) and LPS + memantine (10 mg/kg). Minocycline and memantine were administered intraperitoneally (i.p) for two weeks, and LPS was injected i.p. once on day 5. ELISA was used to determine the level of phosphorylated tau protein in SD rats' hippocampal tissue. The density and expression of Toll-like receptor-4 (TLR-4), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-кβ), tumour necrosis factor-alpha (TNF-α), and cyclooxygenase (COX)-2 were determined using Western blot and immunohistochemistry.

    RESULTS: Minocycline, like memantine, prevented LPS-induced increasein phosphorylated tau protein level suggested via reduced density and expression of TLR-4, NF-кβ, TNF-αand COX-2 proteins in rat hippocampal tissue. Interestingly, higher doses were shown to be more neuroprotective than lower doses.

    CONCLUSION: This study suggests that minocycline suppresses the neuroinflammation signalling pathway and decreased phosphorylated tau protein formation induced by LPS in a dose-dependent manner. Minocycline can be used as a preventative and therapeutic drug for neuroinflammatory diseases such as AD.

  13. Abdo Qaid EY, Abdullah Z, Zakaria R, Long I
    Int J Neurosci, 2024 Jun;134(1):56-65.
    PMID: 35638219 DOI: 10.1080/00207454.2022.2084092
    PURPOSE/AIM: Neuroinflammation and oxidative stress have been encountered in neurodegenerative diseases such as Alzheimer's disease (AD). However, the neuroprotective effects of minocycline against lipopolysaccharide (LPS)-induced glial cells activation and oxidative stress damage in the medial prefrontal cortex (mPFC) of rats are still elusive. The purpose of this study is to investigate the effects of minocycline and memantine, an N-methyl-D-aspartate (NMDA) receptor antagonist, on the microglia and astrocytes expression, as well as oxidative stress levels in the mPFC of LPS injected rats.

    MATERIALS AND METHODS: Fifty adult Male Sprague Dawley rats were divided into five groups: control, LPS (5 mg/kg), LPS treated with minocycline (25 mg/kg), LPS treated with minocycline (50 mg/kg) and LPS treated with memantine (10 mg/kg). The immunohistochemistry and western blotting were used to analyse the expressions and densities of microglia marker (Iba-1) and astrocyte marker, (GFAP) while enzyme-linked immunosorbent assay (ELISA) was used to measure the protein carbonyl (PCO), malondialdehyde (MDA), catalase (CAT), and superoxide dismutase (SOD) levels.

    RESULTS: In comparison to the control group, the expression and density of Iba-1 and GFAP were significantly enhanced in the LPS group (p 

  14. Al-Mohammed NN, Alias Y, Abdullah Z, Shakir RM, Taha EM, Hamid AA
    Molecules, 2013 Sep 26;18(10):11978-95.
    PMID: 24077176 DOI: 10.3390/molecules181011978
    Several new substituted sulfonamide compounds were synthesized and their structures were confirmed by ¹H-NMR, ¹³C-NMR, FT-IR, and mass spectroscopy. The antibacterial activities of the synthesized compounds were screened against standard strains of six Gram positive and four Gram negative bacteria using the microbroth dilution assay. Most of the compounds studied showed promising activities against both types of bacteria.
  15. Al-Mohammed NN, Shakir RM, Alias Y, Abdullah Z, Abd Halim SN, Tiekink ER
    Acta Crystallogr Sect E Struct Rep Online, 2011 Jul 1;67(Pt 7):o1838.
    PMID: 21837205 DOI: 10.1107/S1600536811024664
    The title mol-ecule, C(26)H(30)O(9)S(3), adopts an extended conformation whereby two approximately parallel benzene rings [dihedral angle = 8.32 (10)°] are orientated in opposite directions along the pseudo-threefold axis through the central quaternary C atom, while a third ring occupies a position mid-way and face-on to these rings [dihedral angles = 82.28 (10) and 78.81 (7)°]. The crystal packing is dominated by C-H⋯O contacts and π-π inter-actions [ring centroid distance = 3.6902 (12) Å].
  16. Ishak DH, Tajuddin HA, Abdullah Z, Abd Halim SN, Tiekink ER
    Acta Crystallogr Sect E Struct Rep Online, 2011 Jul 1;67(Pt 7):o1658.
    PMID: 21837058 DOI: 10.1107/S1600536811022409
    In the title compound, C(10)H(9)N(3)O(3), there is a small twist between the benzene and triazole rings [dihedral angle = 6.32 (7)°]; the carb-oxy-lic acid residue is almost coplanar with the benzene ring to which it is attached [O-C-C-C torsion angle = 1.49 (19)°]. The main deviation from coplanarity of the non-H atoms is found for the hy-droxy group which is almost perpendicular to the remaining atoms [N-C-C-O torsion angle = -75.46 (16)°]. In the crystal, the presence of O-H⋯O (between carboxyl groups) and O-H⋯N (between the hy-droxy group and the triazole ring) hydrogen bonds leads to supra-molecular chains along [03[Formula: see text]]. The chains are connected into sheets via C-H⋯O(hy-droxy) inter-actions.
  17. Tan SJ, Low YY, Choo YM, Abdullah Z, Etoh T, Hayashi M, et al.
    J Nat Prod, 2010 Nov 29;73(11):1891-7.
    PMID: 21043460 DOI: 10.1021/np100552b
    A total of 25 alkaloids were isolated from the leaf and stem-bark extracts of Alstonia spatulata, of which five are new alkaloids of the strychnan type (alstolucines A-E, 1-5) and the other, a new alkaloid of the secoangustilobine A type (alstolobine A, 6). The structures of these alkaloids were established using NMR and MS analysis and, in the case of alstolucine B (2), also confirmed by X-ray diffraction analysis. A reinvestigation of the stereochemical assignment of scholaricine (13) by NMR and X-ray analyses indicated that the configuration at C-20 required revision. Alkaloids 1, 2, 6, 7, 9, 10, and 13 reversed multidrug resistance in vincristine-resistant KB cells.
  18. Aznan Akhmad MA, Abdullah Z, Fairuz ZA, Ng SW, Tiekink ER
    PMID: 21588732 DOI: 10.1107/S1600536810033040
    Two independent mol-ecules comprise the asymmetric unit of the title compound, C(12)H(11)N(3)O(2). These differ in terms of the relative orientations of the benzene rings as seen in the respective dihedral angles formed between the pyridine and benzene rings [17.42 (16) and 34.64 (16)°]. Both mol-ecules are twisted about the amine-tolyl N-C bonds [respective torsion angles = 22.3 (5) and 35.9 (5)°] but only about the amine-pyridine N-C bond in the first independent mol-ecule [respective torsion angles = -11.7 (5) and 0.8 (5)°]. Intra-molecular N-H⋯O hydrogen bonds preclude the amine H atoms from forming significant inter-molecular inter-actions. The crystal packing features inter-molecular C-H⋯O and C-H⋯π and π-π [centroid-centroid distance: pyridine-benzene = 3.6442 (19) Å and pyridine-pyridine = 3.722 (2) Å] contacts.
  19. Hassan ND, Abdullah Z, Tajuddin HA, Fairuz ZA, Ng SW, Tiekink ER
    PMID: 21588753 DOI: 10.1107/S1600536810034100
    In the title mol-ecule, C(14)H(9)N(3)O(3), the dihedral angle between the quinoxaline and benzene rings is 77.13 (9)°. The mol-ecule is twisted about the ether-benzene O-C bond, with a C-O-C-C torsion angle of -102.8 (2)°. In the crystal, mol-ecules are linked by C-H⋯O hydrogen bonds, forming layers in the ab plane, with one nitro O atom accepting two such inter-actions. The layers stack along the c-axis direction via weak C-H⋯π inter-actions.
  20. Nasir SB, Abdullah Z, Fairuz ZA, Ng SW, Tiekink ER
    PMID: 21588752 DOI: 10.1107/S1600536810034057
    In the title mol-ecule, C(12)H(10)N(2)O(4), the pyridine and benzene rings are almost orthogonal [dihedral angle = 86.69 (11)°], with the pyridine N atom directed towards the centre of the benzene ring. The -NO(2) [O-N-C-C = -26.1 (3)°] and -OMe [C-O-C-C = 166.5 (2)°] substituents are not coplanar with their respective aromatic rings. In the crystal, supra-molecular layers in the ab plane are formed via C-H⋯π inter-actions involving methyl H atoms and the pyridine and benzene rings. Short N-O⋯π contacts (where the π-system is derived from the pyridine ring) occur between layers in the c-axis direction.
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