Displaying publications 1 - 20 of 79 in total

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  1. Ahmad K, Win T, Jaffri JM, Edueng K, Taher M
    AAPS PharmSciTech, 2018 Jan;19(1):371-383.
    PMID: 28744617 DOI: 10.1208/s12249-017-0843-9
    This study aims to investigate the use of palm olein as the oil phase for betamethasone 17-valerate (BV) emulsions. The physicochemical properties of the formulations were characterized. In vitro drug release study was performed with the Hanson Vertical Diffusion Cell System; the samples were quantified with HPLC and the results were compared with commercial products. Optimized emulsion formulations were subjected to stability studies for 3 months at temperatures of 4, 25, and 40°C; the betamethasone 17-valerate content was analyzed using HPLC. The formulations produced mean particle size of 2-4 μm, viscosities of 50-250 mPa.s, and zeta potential between -45 and -68 mV. The rheological analyses showed that the emulsions exhibited pseudoplastic and viscoelastic behavior. The in vitro release of BV from palm olein emulsion through cellulose acetate was 4.5 times higher than that of commercial products and more BV molecules deposited in rat skin. Less than 4% of the drug was degraded in the formulations during the 3-month period when they were subjected to the three different temperatures. These findings indicate that palm olein-in-water emulsion can be an alternative vehicle for topical drug delivery system with superior permeability.
  2. Othman, M., Ahmad, K.
    ASM Science Journal, 2008;2(2):183-183.
    MyJurnal
    Comet Lulin was discovered by Lin Chi-Sheng and Ye Quanzhi using the 16-inch telescope at Lulin Observatory in Nantou, Taiwan in 2007. According to Brian Marsden of the Smithsonian Astrophysical Observatory, it reached its perihelion on 10 January 2009 at a distance of 113 million
    km from the Sun. It moves in a very nearly parabolic retrograde (‘backwards’ compared to the movement of the planets) orbit at an inclination of 1.6 degrees from the ecliptic (“Newfound Comet Lulin to Grace Night Skies”). http://www.space.com/spacewatch/090206-ns-cometlulin.html). It passed nearest to the Earth at a distance of 61 million km on 23 February 2009.
  3. Othman, M., Ahmad, K.
    ASM Science Journal, 2007;1(2):181-182.
    MyJurnal
    Comet 17P/Holmes was discovered by Edwin Holmes on 6 November 1892 while he was conducting regular observations of the Andromeda Galaxy (M31). Calculations using observation of its orbits established the perihelion date as 13 June and the orbital period as 6.9 years. The 1899 and 1906 appearances were observed, but the comet was only seen again in 1964. The comet has since been
    observed on every subsequent return.
  4. Mohamad K, Yusoff M, Awang K, Ahmad K, Ng SW
    PMID: 21583174 DOI: 10.1107/S1600536809015955
    In the mol-ecule of pinnatane A, C(30)H(48)O(3), isolated from the bark of Walsura pinnata Hassk, the four cyclo-hexane rings adopt chair conformations; the carboxyl and hydr-oxy substituents occupy axial positions. The cyclo-hexene ring is envelope-shaped. Adjacent mol-ecules are linked by O-H⋯O hydrogen bonds into a chain running along the c axis.
  5. Ahmad K, Thomas NF, Nafiah MA, Awang K, Ng SW
    PMID: 21583151 DOI: 10.1107/S1600536809017401
    In the title compound, C(17)H(17)NO(2), the phenyl-ene rings are bent with respect to the carbon-carbon double bond [dihedral angle between rings = 39.6 (1)°]. The acetamido group is twisted out of the plane of the aromatic ring [dihedral angle = 44.2 (1)°] in order to form an N-H⋯O hydrogen bond to the acetamido group of an adjacent mol-ecule, generating a zigzag chain running along the c axis.
  6. Ahmad K, Thomas NF, Din MF, Awang K, Ng SW
    PMID: 21583150 DOI: 10.1107/S1600536809017395
    In the title compound, C(17)H(17)NO(2), the phenyl-ene rings are nearly coplanar [dihedral angle 7.3 (1)°]. The acetamido group is twisted out of the plane of the aromatic ring in order to form an N-H⋯O hydrogen bond to the acetamido group of an adjacent mol-ecule, generating a helical chain running along the b axis.
  7. Arshad ZI, Amid A, Yusof F, Jaswir I, Ahmad K, Loke SP
    Appl Microbiol Biotechnol, 2014 Sep;98(17):7283-97.
    PMID: 24965557 DOI: 10.1007/s00253-014-5889-y
    This review highlights the use of bromelain in various applications with up-to-date literature on the purification of bromelain from pineapple fruit and waste such as peel, core, crown, and leaves. Bromelain, a cysteine protease, has been exploited commercially in many applications in the food, beverage, tenderization, cosmetic, pharmaceutical, and textile industries. Researchers worldwide have been directing their interest to purification strategies by applying conventional and modern approaches, such as manipulating the pH, affinity, hydrophobicity, and temperature conditions in accord with the unique properties of bromelain. The amount of downstream processing will depend on its intended application in industries. The breakthrough of recombinant DNA technology has facilitated the large-scale production and purification of recombinant bromelain for novel applications in the future.
  8. Lim GC, Aina EN, Cheah SK, Ismail F, Ho GF, Tho LM, et al.
    BMC Cancer, 2014;14:212.
    PMID: 24650245 DOI: 10.1186/1471-2407-14-212
    BACKGROUND: Cancer is the leading cause of deaths in the world. A widening disparity in cancer burden has emerged between high income and low-middle income countries. Closing this cancer divide is an ethical imperative but there is a dearth of data on cancer services from developing countries.
    METHODS: This was a multi-center, retrospective observational cohort study which enrolled women with breast cancer (BC) attending 8 participating cancer centers in Malaysia in 2011. All patients were followed up for 12 months from diagnosis to determine their access to therapies. We assess care performance using measures developed by Quality Oncology Practice Initiative, American Society of Clinical Oncology/National Comprehensive Cancer Network, American College of Surgeons' National Accreditation Program for Breast Centers as well as our local guideline.
    RESULTS: Seven hundred and fifty seven patients were included in the study; they represent about 20% of incident BC in Malaysia. Performance results were mixed. Late presentation was 40%. Access to diagnostic and breast surgery services were timely; the interval from presentation to tissue diagnosis was short (median = 9 days), and all who needed surgery could receive it with only a short wait (median = 11 days). Performance of radiation, chemo and hormonal therapy services showed that about 75 to 80% of patients could access these treatments timely, and those who could not were because they sought alternative treatment or they refused treatment. Access to Trastuzumab was limited to only 19% of eligible patients.
    CONCLUSIONS: These performance results are probably acceptable for a middle income country though far below the 95% or higher adherence rates routinely reported by centres in developed countries. High cost trastuzumab was inaccessible to this population without public funding support.
  9. Ngew KY, Tay HZ, Yusof AKM
    BMC Cardiovasc Disord, 2023 Nov 08;23(1):545.
    PMID: 37940867 DOI: 10.1186/s12872-023-03536-w
    PURPOSE: Percutaneous coronary intervention (PCI) is a common treatment modality for coronary artery disease. Accurate prediction of patients at risk for complications and hospital readmission after PCI could improve the overall clinical management. We aimed to develop and validate predictive models to predict any cardiac event within a year post PCI procedure.

    METHODS: This is a retrospective cohort study utilizing data from the National Cardiovascular Disease (NCVD)-PCI registry. The data collected (N = 28,007) were split into training set (n = 24,409) and testing set (n = 3598). Four predictive models (logistic regression [LR], random forest method, support vector machine [SVM], and artificial neural network) were developed and validated. The outcome on risk prediction were compared.

    RESULTS: The demographic and clinical features of patients in the training and testing cohorts were similar. Patients had mean age ± standard deviation of 58.15 ± 10.13 years at admission with a male majority (82.66%). In over half of the procedures (50.61%), patients had chronic stable angina. Within 1 year of follow up mortality, target vessel revascularization (TVR), and composite event of mortality and TVR were 3.92%, 9.48%, and 12.98% respectively. LR was the best model in predicting mortality event within 1-year post-PCI (AUC: 0.820). SVM had the highest discrimination power for both TVR event (AUC: 0.720) and composite event of mortality and TVR (AUC: 0.720).

    CONCLUSIONS: This study successfully identified optimal prediction models with the good discriminatory ability for mortality outcome and good discrimination ability for TVR and composite event of mortality and TVR with a simple machine learning framework.

  10. Chen A, Azriff Basri A, Ismail NB, Arifin Ahmad K
    Bioengineering (Basel), 2023 Mar 01;10(3).
    PMID: 36978704 DOI: 10.3390/bioengineering10030312
    Subaortic stenosis (SAS) is a common congenital heart disease that can cause significant morbidity and mortality if not treated promptly. Patients with heart valve disease are prone to complications after replacement surgery, and the existence of SAS can accelerates disease progression, so timely diagnosis and treatment are required. However, the effects of subaortic stenosis on mechanical heart valves (MHV) are unknown. This study aimed to investigate flow characteristics in the presence of subaortic stenosis and computationally quantify the effects on the hemodynamics of MHV. Through the numerical simulation method, the flow characteristics and related parameters in the presence of SAS can be more intuitively observed. Based on its structure, there are three types of SAS: Tunnel-type SAS (TSS); Fibromuscular annulus SAS (FSS); Discrete SAS (DSS). The first numerical simulation study on different types of SAS found that there are obvious differences among them. Among them, the tunnel-type SAS formed a separated vortex structure on the tunnel-type narrow surface, which exhibits higher wall shear force at a low obstacle percentage. However, discrete SAS showed obvious differences when there was a high percentage of obstacles, forming high peak flow, high wall shear stress, and a high-intensity complex vortex. The presence of all three types of SAS results in the formation of high-velocity jets and complex vortices in front of the MHV, leading to increased shear stress and stagnation time. These hemodynamic changes significantly increase the risk of MHV dysfunction and the development of complications. Despite differences between the three types of SAS, the resultant effects on MHV hemodynamics are consistent. Therefore, early surgical intervention is warranted in SAS patients with implanted MHV.
  11. Hossain MI, Ahmad K, Vadamalai G, Siddiqui Y, Saad N, Ahmed OH, et al.
    Biology (Basel), 2021 Sep 03;10(9).
    PMID: 34571739 DOI: 10.3390/biology10090862
    Colletotrichum falcatum Went causes red rot disease in sugarcane farming in the tropical and sub-tropical regions. This disease causes significant economic loss to the sugarcane production industry. Successful disease management strategies depend on understanding the evolutionary relationship between pathogens, genetic diversity, and population structure, particularly at the intra-specific level. Forty-one isolates of C. falcatum were collected from different sugarcane farms across Bangladesh for molecular identification, phylogeny and genetic diversity study. The four genes namely, ITS-rDNA, β-tubulin, Actin and GAPDH sequences were conducted. All the 41 C. falcatum isolates showed a 99-100% similarity index to the conserved gene sequences in the GenBank database. The phylogram of the four genes revealed that C. falcatum isolates of Bangladesh clustered in the same clade and no distinct geographical structuring were evident within the clade. The four gene sequences revealed that C. falcatum isolates from Bangladesh differed from other countries´ isolates because of nucleotides substitution at different loci. The genetic structure of C. falcatum isolates were determined using ISSR marker generated 404 polymorphic loci from 10 selected markers. The percentage of polymorphic loci was 99.01. The genetic variability at species level was slightly higher than at population level. Total mean gene diversity at the species level was 0.1732 whereas at population level it was 0.1521. The cluster analysis divided 41 isolates into four main genetic groups and the principal component analysis was consistent with cluster analysis. To the best of our knowledge, this is the first finding on characterizing C. falcatum isolates infesting sugarcane in Bangladesh. The results of this present study provide important baseline information vis a vis C. falcatum phylogeny analysis and genetic diversity study.
  12. Kutawa AB, Ahmad K, Ali A, Hussein MZ, Abdul Wahab MA, Adamu A, et al.
    Biology (Basel), 2021 Sep 08;10(9).
    PMID: 34571758 DOI: 10.3390/biology10090881
    Approximately 15-18% of crops losses occur as a result of animal pests, while weeds and microbial diseases cause 34 and 16% losses, respectively. Fungal pathogens cause about 70-80% losses in yield. The present strategies for plant disease control depend transcendently on agrochemicals that cause negative effects on the environment and humans. Nanotechnology can help by reducing the negative impact of the fungicides, such as enhancing the solubility of low water-soluble fungicides, increasing the shelf-life, and reducing toxicity, in a sustainable and eco-friendly manner. Despite many advantages of the utilization of nanoparticles, very few nanoparticle-based products have so far been produced in commercial quantities for agricultural purposes. The shortage of commercial uses may be associated with many factors, for example, a lack of pest crop host systems usage and the insufficient number of field trials. In some areas, nanotechnology has been advanced, and the best way to be in touch with the advances in nanotechnology in agriculture is to understand the major aspect of the research and to address the scientific gaps in order to facilitate the development which can provide a rationale of different nanoproducts in commercial quantity. In this review, we, therefore, described the properties and synthesis of nanoparticles, their utilization for plant pathogenic fungal disease control (either in the form of (a) nanoparticles alone, that act as a protectant or (b) in the form of a nanocarrier for different fungicides), nano-formulations of agro-nanofungicides, Zataria multiflora, and ginger essential oils to control plant pathogenic fungi, as well as the biosafety and limitations of the nanoparticles applications.
  13. Haider MR, Ahmad K, Siddiqui N, Ali Z, Akhtar MJ, Fuloria N, et al.
    Bioorg Chem, 2019 07;88:102962.
    PMID: 31085373 DOI: 10.1016/j.bioorg.2019.102962
    A series of 9-(2-(1-arylethylidene)hydrazinyl)acridine and its analogs were designed, synthesized and evaluated for biological activities. Various biochemical assays were performed to determine the free radical scavenging capacity of synthesized compounds (4a-4j). Anticancer activity of these compounds was assessed against two different human cancer cell lines viz cervical cancer cells (HeLa) and liver cancer cells (HepG2) as well as normal human embryonic kidney cell line (HEK 293). Compounds 4b, 4d and 4e showed potential anti-proliferative effects on HeLa cells. Based on results obtained from antioxidant and cytotoxicity studies, 4b, 4d and 4e were further studied in detail for different biological activities. 4b, 4d and 4e reduced the cell growth, inhibited metastatic activity and declined the potential of cell migration in HeLa cell lines. Topoisomerase1 (Top1) treated with compounds 4b, 4d and 4e exhibited inhibition of Top1 and prevented DNA replication. Molecular docking results validate that interaction of compounds 4b, 4d and 4e with Top1-DNA complex, which might be accountable for their inhibitory effects. Further it was concluded that compounds 4b, 4d and 4e arrests the cells at S phase and consequently induces cell death through DNA damage in HeLa cells.
  14. Shafiei SNS, Ahmad K, Ikhsan NFM, Ismail SI, Sijam K
    Braz J Biol, 2020 2 20;81(1):11-17.
    PMID: 32074168 DOI: 10.1590/1519-6984.206124
    Xanthomonas oryzae pv. oryzae (Xoo), a pathogen responsible for rice bacterial leaf blight, produces biofilm to protect viable Xoo cells from antimicrobial agents. A study was conducted to determine the potency of Acacia mangium methanol (AMMH) leaf extract as a Xoo biofilm inhibitor. Four concentrations (3.13, 6.25, 9.38, and 12.5 mg/mL) of AMMH leaf extract were tested for their ability to inhibit Xoo biofilm formation on a 96-well microtiter plate. The results showed that the negative controls had the highest O.D. values from other treatments, indicating the intense formation of biofilm. This was followed by the positive control (Streptomycin sulfate, 0.2 mg/mL) and AMMH leaf extract at concentration 3.13 mg/mL, which showed no significant differences in their O.D. values (1.96 and 1.57, respectively). All other treatments at concentrations of 6.25, 9.38, and 12.5 mg/mL showed no significant differences in their O.D. values (0.91, 0.79, and 0.53, respectively). For inhibition percentages, treatment with concentration 12.5 mg/mL gave the highest result (81.25%) followed by treatment at concentrations 6.25 and 9.38 mg/mL that showed no significant differences in their inhibition percentage (67.75% and 72.23%, respectively). Concentration 3.13 mg/mL resulted in 44.49% of biofilm inhibition and the positive control resulted in 30.75% of biofilm inhibition. Confocal laser scanning microscopy (CLSM) analysis of Xoo biofilm inhibition and breakdown showed the presence of non-viable Xoo cells and changes in aggregation size due to increase in AMMH leaf extract concentration. Control slides showed the absence of Xoo dead cells.
  15. Ahmadu T, Ahmad K, Ismail SI, Rashed O, Asib N, Omar D
    Braz J Biol, 2020 11 12;81(4):1007-1022.
    PMID: 33175006 DOI: 10.1590/1519-6984.233173
    Drawbacks associated with the use of chemical fungicides to control plant pathogenic fungi such as Botrytis cinerea stimulate the need for alternatives. Therefore, the present study was carried out to determine the antifungal potentials of Moringa oleifera extracts against B. cinerea. Phytochemical analysis using qualitative chemical tests revealed the presence of huge amount of crucial phytochemicals compounds like phenolic compounds, alkaloids and saponins in the M. oleifera leaf extract. Antifungal bioassay of the crude extracts indicated better mycelial growth inhibition by methanol leaf extract (99%). The minimum inhibitory concentration (MIC) was 5 mg/ml with 100% spore germination inhibition and minimum fungicidal concentration (MFC) was 10 mg/ml with 98.10% mycelial growth inhibition using broth micro dilution and poisoned food techniques. Gas chromatography-mass spectrometry (GC-MS) analysis led to the identification of 67 volatile chemical compounds in the leaf extract with 6-decenoic acid (Z)- (19.87%) was the predominant compound. Further chemical elucidation of the crude extracts performed by liquid chromatography with tandem mass spectrometry (LC-MS/MS) showed the presence of non-volatile chemical compounds, mostly flavones, flavonoids and phenolic acids (i.e. quercetin and kaempferol). Scanning electron microscopy and transmission electron microscopy analysis showed positive effect of M. oleifera leaf extract on the treated conidia and mycelium of B. cinerea. Findings revealed that irreversible surface and ultra-structural changes with severe detrimental effects on conidia and mycelium morphology compared to control treatment. Overall findings suggested that M. oleifera leaf extract is a promising candidate for biological control of fungal pathogens, thus limiting overdependence on chemical fungicides.
  16. Yazid SN, Ahmad K, Razak MSFA, Rahman ZA, Ramachandran K, Mohamad SNA, et al.
    Braz J Biol, 2021;84:e248359.
    PMID: 34730685 DOI: 10.1590/1519-6984.248359
    Bacterial leaf blight (BLB) is one of the major rice diseases in Malaysia. This disease causes substantial yield loss as high as 70%. Development of rice varieties which inherited BLB resistant traits is a crucial approach to promote and sustain rice industry in Malaysia. Hence, this study aims were to enhance BLB disease resistant characters of high yielding commercial variety MR219 through backcross breeding approach with supporting tool of marker-assisted selection (MAS). Broad spectrum BLB resistance gene, Xa7 from donor parent IRBB7 were introgressed into the susceptible MR219 (recurrent parent) using two flanking markers ID7 and ID15. At BC3F4, we managed to generate 19 introgressed lines with homozygous Xa7 gene and showed resistant characteristics as donor parent when it was challenged with Xanthomonas oryzae pv. oryzae through artificial inoculation. Recurrent parent MR219 and control variety, MR263 were found to be severely infected by the disease. The improved lines exhibited similar morphological and yield performance characters as to the elite variety, MR219. Two lines, PB-2-107 and PB-2-34 were chosen to be potential lines because of their outstanding performances compared to parent, MR219. This study demonstrates a success story of MAS application in development of improved disease resistance lines of rice against BLB disease.
  17. Borhanuddin BK, Abdul Latiff H, Mohamed Yusof AK
    Cardiol Young, 2022 Dec;32(12):1994-1998.
    PMID: 35707919 DOI: 10.1017/S1047951122000154
    BACKGROUND: CT is an accepted non-invasive imaging tool to assess the coronary arteries in adults; however, its utilisation in children is limited by high heart rate and lack of standardised protocol. We sought to assess diagnostic quality and factors that affect image quality of CT in assessing coronary artery lesions in Kawasaki patients less than 18 years of age.

    METHODOLOGY: CT coronary angiography was performed on patients with Kawasaki disease diagnosed with coronary aneurysm or suspected to have coronary stenosis. Studies were performed using electrocardiogram-gated protocols. General anaesthesia was used in patients who were not cooperative for breathing control. Heart rate, image quality, and effective radiation dose were documented.

    RESULTS: Fifty-two Kawasaki patients underwent CT coronary angiography to assess coronary artery lesions. Median heart rate was 88 beats per minute (range 50-165 beats/minute). Image quality was graded as excellent in 34 (65%) patients, good in 17 (32%), satisfactory in 1, and poor in 1 patient. Coronary artery aneurysm was found in 25 (bilateral = 6, unilateral = 19, multiple = 11). Thrombus was found in 11 patients resulting in partial and total occlusion in 8 and 3 patients, respectively. Coronary stenosis was noted in 2 patients. The effective radiation dose was 1.296 millisievert (median 0.81 millisievert). Better diagnostic imaging quality was significantly related to lower heart rate (p = 0.007).

    CONCLUSION: Electrocardiogram-triggered CT coronary angiography provides a good diagnostic assessment of coronary artery lesions in children with Kawasaki disease.

  18. Ahmad K, Thomas NF, Hadi AH, Mukhtar MR, Mohamad K, Nafiah MA, et al.
    Chem Pharm Bull (Tokyo), 2010 Aug;58(8):1085-7.
    PMID: 20686264
    A phytochemical study on the bark of Neisosperma oppositifolia (Apocynaceae) yielded two new beta-carboline indole alkaloids, oppositinines A (1) and B (2), together with five known alkaloids, isoreserpiline, isocarapanaubine, vobasine, 10-methoxydihydrocorynantheol-N-oxide, and ochropposinine oxindole. Structural elucidation of 1 and 2 was performed using 2D NMR methods. Oppositinines A (1) and B (2) showed potent vasorelaxant effects on the rat aorta.
  19. Tiran Gunasena M, Hussein MZ, Ali A, Wahab MAA, Bashir Kutawa A, Rafif A, et al.
    Chem Biodivers, 2023 Dec;20(12):e202300686.
    PMID: 37905394 DOI: 10.1002/cbdv.202300686
    Ginger essential oils (GEO) shows exceptional antimicrobial properties against plant pathogens. Due to its high volatility and low stability, it requires encapsulation to retain its effective properties. The GEO-Chitosan (GEO-CS) nanobactericide was developed using the ionic gelation method. The nanobactericides show particle diameters of 465, 28, 35, 48 and 500 nm when sodium tripolyphosphate (TPP) concentrations used in the preparation were 0.0, 0.5, 1.0, 2.0 and 4.0 %, respectively. The X-ray diffraction and the UV-vis studies revealed that the GEO was encapsulated into the chitosan nanoparticles with an encapsulation efficiency of around 46 % and a loading capacity of 27-34 %. The antibacterial activity of GEO-chitosan nanobactericide against Burkholderia glumae (Bg) was found to be 7.5-11.8 mm, with minimum inhibitory concentration and minimum bactericidal concentration values of 15.6 μl/mL and 31.25 μl/mL, respectively. Hence, these findings indicate that the prepared GEO-CS nanobactericides were found to be effective against Bg. This preliminary study is toward the development of new agronanobactericides using a natural product to control Bg.
  20. Anis FN, Umat C, Ahmad K, Hamid BA
    Cochlear Implants Int, 2019 01;20(1):12-22.
    PMID: 30293522 DOI: 10.1080/14670100.2018.1530420
    OBJECTIVE: This study examined the patterns of recognition of Arabic consonants, via information transmission analysis for phonological features, in a group of Malay children with normal hearing (NH) and cochlear implants (CI).

    METHOD: A total of 336 and 616 acoustic tokens were collected from six CI and 11 NH Malay children, respectively. The groups were matched for hearing age and duration of exposure to Arabic sounds. All the 28 Arabic consonants in the form of consonant-vowel /a/ were presented randomly twice via a loudspeaker at approximately 65 dB SPL. The participants were asked to repeat verbally the stimulus heard in each presentation.

    RESULTS: Within the native Malay perceptual space, the two groups responded differently to the Arabic consonants. The dispersed uncategorized assimilation in the CI group was distinct in the confusion matrix (CM), as compared to the NH children. Consonants /ħ/, /tˁ/, /sˁ/ and /ʁ/ were difficult for the CI children, while the most accurate item was /k/ (84%). The CI group transmitted significantly reduced information, especially for place feature transmission, then the NH group (p 

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