Displaying publications 41 - 60 of 96 in total

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  1. Kia Y, Osman H, Kumar RS, Murugaiyah V, Basiri A, Perumal S, et al.
    Bioorg Med Chem Lett, 2013 May 15;23(10):2979-83.
    PMID: 23570788 DOI: 10.1016/j.bmcl.2013.03.027
    A series of novel hybrid spiro heterocycles comprising pyrrolizine, spiroxindole and piperidine moieties was synthesized chemo-, regio- and stereoselectively in good yields from 1,3-dipolar cycloaddition reaction of a series of 1-acryloyl-3,5-bisarylmethylidenepiperidin-4-ones with azomethine ylides generated in situ from 5-choloroisatin and l-proline in methanol. These cycloadducts displayed significant cholinesterase inhibitory activity. Among the compounds screened, 8g and 8e, showed maximum inhibitory activity against acetylcholinesterase (AChE) and butyrylcholinestrase (BChE) with IC50 values of 3.33 and 3.13μM, respectively.
  2. Wong KT, Osman H, Parumasivam T, Supratman U, Che Omar MT, Azmi MN
    Molecules, 2021 Apr 05;26(7).
    PMID: 33916423 DOI: 10.3390/molecules26072081
    A total of fourteen pyrazoline derivatives were synthesized through cyclo-condensation reactions by chalcone derivatives with different types of semicarbazide. These compounds were characterized by IR, 1D-NMR (1H, 13C and Distortionless Enhancement by Polarization Transfer - DEPT-135) and 2D-NMR (COSY, HSQC and HMBC) as well as mass spectroscopy analysis (HRMS). The synthesized compounds were tested for their antituberculosis activity against Mycobacterium tuberculosis H37Ra in vitro. Based on this activity, compound 4a showed the most potent inhibitory activity, with a minimum inhibitory concentration (MIC) value of 17 μM. In addition, six other synthesized compounds, 5a and 5c-5g, exhibited moderate activity, with MIC ranges between 60 μM to 140 μM. Compound 4a showed good bactericidal activity with a minimum bactericidal concentration (MBC) value of 34 μM against Mycobacterium tuberculosis H37Ra. Molecular docking studies for compound 4a on alpha-sterol demethylase was done to understand and explore ligand-receptor interactions, and to hypothesize potential refinements for the compound.
  3. Leong MC, Latiff HA, Hew CC, Mazlan SL, Osman H
    Echocardiography, 2013 Feb;30(2):E33-5.
    PMID: 23134298 DOI: 10.1111/echo.12044
    An inverted left atrial appendage is a rare phenomenon post cardiac surgery. The lesion presents as an additional mass in the left atrium, which would trigger unnecessary concerns and frequently, a battery of tests. The lesion can be easily diagnosed using echocardiography. We report a case of inverted left atrial appendage in a patient post repair of common arterial trunk. Echocardiographic pictures and features which help to identify this lesion as well as to differentiate it from other possible left atrial mass are described. This article aimed to improve the awareness of sonographers toward this rare but possible post operative lesion.
  4. Bharkavi C, Vivek Kumar S, Ashraf Ali M, Osman H, Muthusubramanian S, Perumal S
    Bioorg Med Chem, 2016 11 15;24(22):5873-5883.
    PMID: 27687968 DOI: 10.1016/j.bmc.2016.09.044
    A facile stereoselective synthesis of novel dispiro indeno pyrrolidine/pyrrolothiazole-thiochroman hybrids has been achieved by 1,3-dipolar cycloaddition of azomethine ylides, generated in situ from ninhydrin and sarcosine/thiaproline, on a series of 3-benzylidenethiochroman-4-ones. The synthesised compounds were screened for their antimycobacterial, anticancer and AchE inhibition activities. Compound 4l (IC50 1.07μM) has been found to exhibit the most potent antimycobacterial activity compared to cycloserine (12 times), pyrimethamine (37 times) and ethambutol (IC50 <1.56μM) and 6l (IC50=2.87μM) is more active than both cycloserine (4 times) and pyrimethamine (12 times). Three compounds, 4a, 6b and 6i, display good anticancer activity against CCRF-CEM cell lines. Compounds 6g and 4g display maximum AchE inhibitory activity with IC50 values of 1.10 and 1.16μmol/L respectively.
  5. Hui BY, Raoov M, Zain NNM, Mohamad S, Osman H
    Crit Rev Anal Chem, 2017 Sep 03;47(5):454-467.
    PMID: 28453309 DOI: 10.1080/10408347.2017.1320936
    The growth in driving force and popularity of cyclodextrin (CDs) and ionic liquids (ILs) as promising materials in the field of analytical chemistry has resulted in an exponentially increase of their exploitation and production in analytical chemistry field. CDs belong to the family of cyclic oligosaccharides composing of α-(1,4) linked glucopyranose subunits and possess a cage-like supramolecular structure. This structure enables chemical reactions to proceed between interacting ions, radical or molecules in the absence of covalent bonds. Conversely, ILs are an ionic fluids comprising of only cation and anion often with immeasurable vapor pressure making them as green or designer solvent. The cooperative effect between CD and IL due to their fascinating properties, have nowadays contributed their footprints for a better development in analytical chemistry nowadays. This comprehensive review serves to give an overview on some of the recent studies and provides an analytical trend for the application of CDs with the combination of ILs that possess beneficial and remarkable effects in analytical chemistry including their use in various sample preparation techniques such as solid phase extraction, magnetic solid phase extraction, cloud point extraction, microextraction, and separation techniques which includes gas chromatography, high-performance liquid chromatography, capillary electrophoresis as well as applications of electrochemical sensors as electrode modifiers with references to recent applications. This review will highlight the nature of interactions and synergic effects between CDs, ILs, and analytes. It is hoped that this review will stimulate further research in analytical chemistry.
  6. Yeong KY, Liew WL, Murugaiyah V, Ang CW, Osman H, Tan SC
    Bioorg Chem, 2017 02;70:27-33.
    PMID: 27863748 DOI: 10.1016/j.bioorg.2016.11.005
    A series of novel cholinesterase inhibitors containing nitrobenzoate core structure were synthesized by a facile and efficient method. The structure of the novel compounds were fully characterized and confirmed by analytical as well as spectroscopic methods. Compound indicated as 2f was found to possess the best cholinesterase inhibitory activities of all the evaluated compounds. Results suggest that 2f is a selective acetylcholinesterase inhibitor, although it also inhibits butyrylcholinesterase at higher concentration. Kinetics inhibition result suggest that 2f is a mixed-mode inhibitor of acetylcholinesterase. In addition, it was found to have low cytotoxicity. Molecular docking on compound 2f was carried out to rationalize the observed in vitro enzymatic assay results. Most importantly, the potential of nitrobenzoate derivatives as cholinesterase inhibitor was shown through this study. In summary, we discovered nitrobenzoates as a new scaffold that may eventually yield useful compounds in treatment of Alzheimer's disease.
  7. Osman H, Idris NH, Kamarulzaman EE, Wahab HA, Hassan MZ
    Acta Pharm Sin B, 2017 Jul;7(4):479-484.
    PMID: 28752033 DOI: 10.1016/j.apsb.2017.04.009
    Dengue is a severe mosquito-borne viral infection causing half a million deaths annually. Dengue virus NS2B/NS3 protease is a validated target for anti-dengue drug design. A series of hitherto unreported 3,5-bis(arylidene)-4-piperidones analogues 4a-4j were synthesized and screened in silico against DENV2 NS2B/NS3 protease to elucidate their binding mechanism and orientation around the active sites. Results were validated through an in vitro DENV2 NS2B/NS3 protease assay using a fluorogenic Boc-Gly-Arg-Arg-AMC substrate. Nitro derivatives of 3,5-bis(arylidene)-4-piperidones (4e and 4j) emerged as promising lead molecules for novel protease inhibitors with an IC50 of 15.22 and 16.23 µmol/L, respectively, compared to the standard, panduratin A, having IC50 of 57.28 µmol/L.
  8. Yusufzai SK, Khan MS, Sulaiman O, Osman H, Lamjin DN
    Chem Cent J, 2018 Dec 04;12(1):128.
    PMID: 30515636 DOI: 10.1186/s13065-018-0497-z
    Coumarins are the phytochemicals, which belong to the family of benzopyrone, that display interesting pharmacological properties. Several natural, synthetic and semisynthetic coumarin derivatives have been discovered in decades for their applicability as lead structures as drugs. Coumarin based conjugates have been described as potential AChE, BuChE, MAO and β-amyloid inhibitors. Therefore, the objective of this review is to focus on the construction of these pharmacologically important coumarin analogues with anti-Alzheimer's activities, highlight their docking studies and structure-activity relationships based on their substitution pattern with respect to the selected positions on the chromen ring by emphasising on the research reports conducted in between year 1968 to 2017.
  9. Al-Refai M, Ibrahim MM, Azmi MN, Osman H, Bakar MHA, Geyer A
    Molecules, 2019 Nov 10;24(22).
    PMID: 31717690 DOI: 10.3390/molecules24224072
    A series of 2-methoxypyridine-3-carbonitrile (5a-i)-bearing aryl substituents were successfully synthesized in good yields by the condensation of chalcones (4a-i) with malononitrile in basic medium. The condensation process, in most cases, offers a route to a variety of methoxypyridine derivatives (6a-g) as side products in poor yields. All new compounds were fully characterized using different spectroscopic methods. Mass ESI-HMRS measurements were also performed. Furthermore, these compounds were screened for their in vitro cytotoxicity activities against three cancer cell lines; namely, those of the liver (line HepG2), prostate (line DU145) and breast (line MBA-MB-231). The cytotoxicity assessment revealed that compounds 5d, 5g, 5h and 5i exhibit promising antiproliferative effects (IC50 1-5 µM) against those three cancer cell lines.
  10. Yih Hui B, Mohamad Zain NN, Mohamad S, Varanusupakul P, Osman H, Raoov M
    Food Chem, 2020 Jun 01;314:126214.
    PMID: 31972404 DOI: 10.1016/j.foodchem.2020.126214
    Poly(β-cyclodextrin-ionic liquid) grafted magnetic nanoparticles combined with 1-octanol as supramolecular solvents (SUPRASs) presenting new ferrofluid was developed and successfully applied in the dispersive liquid-phase microextraction of seven representative polycyclic aromatic hydrocarbons. One variable at-a-time (OVAT) analysis and response surface methodology (RSM) were used for efficient optimization of the main variables. The calibration curves were found to be linear in the range of 0.1-150 ng mL-1 with correlation of determinations (R2) ranging from 0.9944 to 0.9986. Detection limits ranged at 0.02-0.07 ng mL-1 for all studied PAHs. The intra and inter-day precision values (RSD %) were in the range of 1.80%-7.56% and 2.97%-8.23%, respectively. The ferrofluid showed a satisfactory reproducibility between 1.72% and 5.90%, and acceptable recovery values at 84%-110% were obtained for the real samples analysis. The optimized method was successfully applied to access the content safety of the PAHs studied in a variety of commercial food and beverages available in Malaysia.
  11. Ramachandran T, Faruque MRI, Islam MT, Khandaker MU, Osman H, Boukhris I
    Materials (Basel), 2022 Oct 24;15(21).
    PMID: 36363039 DOI: 10.3390/ma15217447
    This study aimed to investigate the compact 1-bit coding metamaterial design with various conventional and cuboid shapes by analysing the bistatic scattering patterns as well as the monostatic radar cross-section for microwave applications. The construction of this metamaterial design depends on binary elements. For example, 1-bit coding metamaterial comprises two kinds of unit cell to mimic both coding particles such as '0' and '1' with 0° and 180° phase responses. This study adopted a 1 mm × 1 mm of epoxy resin fibre (FR-4) substrate material, which possesses a dielectric constant of 4.3 and tangent loss of 0.025, to construct both elements for the 1-bit coding metamaterial. All simulations were performed using the well-known Computer Simulation Technology (CST) software. The elements were selected via a trial-and-error method based on the phase response properties of the designs. On the other hand, the phase response properties from CST software were validated through the comparison of the phase response properties of both elements with the analytical data from HFSS software. Clear closure was obtained from these findings, and it was concluded that the proposed conventional coding metamaterial manifested the lowest RCS values with an increasing number of lattices. However, the cuboid-shaped design with 20 lattices demonstrated an optimised bistatic scattering pattern of -8.49 dBm2. Additionally, the monostatic RCS values were successfully reduced within the 12 to 18 GHz frequency range with -30 to -10 dBm2 values. In short, the introduced designs were suitable for the proposed application field, and this unique phenomenon is described as the novelty of this study.
  12. Prabhu NS, Somashekarappa HM, Sayyed MI, Osman H, Alamri S, Khandaker MU, et al.
    Materials (Basel), 2021 Nov 17;14(22).
    PMID: 34832355 DOI: 10.3390/ma14226955
    A Yb3+-doped borate glass system was examined for the structural and optical modifications after γ-irradiation. Among the studied 10BaO-20ZnO-20LiF-(50-x)B2O3-xYb2O3 (x = 0.1, 0.5, 0.7, and 1.0 mol%) glasses, the 10BaO-20ZnO-20LiF-49.9B2O3-0.1Yb2O3 glass showed the highest thermoluminescence intensity, trap density, and trap depth. The glass was irradiated with the optimum γ-dose of 1 kGy towards the analysis of radiation-induced defects. The amorphous nature was preserved before and after irradiation. The glass density slightly increased after irradiation. The structural rearrangement was evident from the Fourier transform infrared spectroscopy by the appearance and disappearance of some bonds after γ-irradiation. The transformation of [BO4] units into [BO3] units and non-bridging oxygens was deduced. The color of the glass darkened after irradiation and the optical absorption intensity enhanced between 250 and 700 nm. The optical bandgap reduced and Urbach energy increased upon γ-dose exposure. The electron spin resonance of the irradiated glass exhibited two signals at g = 2.0167 and g = 1.9938, corresponding to the non-bridging oxygen hole center and Boron E'-center, respectively.
  13. Mohamad S, Ismail NN, Parumasivam T, Ibrahim P, Osman H, A Wahab H
    BMC Complement Altern Med, 2018 Jan 08;18(1):5.
    PMID: 29310671 DOI: 10.1186/s12906-017-2077-5
    BACKGROUND: Costus speciosus, Cymbopogon citratus, and Tabernaemontana coronaria are herbal plants traditionally used as remedies for symptoms of tuberculosis (TB) including cough. The aims of the present study were to evaluate the in vitro anti-TB activity of different solvent partitions of these plants, to identify the phytochemical compounds, and to assess the effects of the most active partitions on the growth kinetics and cellular integrity of the tubercle organism.

    METHODS: The in vitro anti-TB activity of different solvent partitions of the plant materials was determined against M. tuberculosis H37Rv using a tetrazolium colorimetric microdilution assay. The phytochemical compounds in the most active partition of each plant were identified using gas chromatography-mass spectrometry (GC-MS) analysis. The effects of these partitions on the growth kinetics of the mycobacteria were evaluated over 7-day treatment period in a batch culture system. Their effects on the mycobacterial cellular integrity were observed under a scanning electron microscope (SEM).

    RESULTS: The respective n-hexane partition of C. speciosus, C. citratus, and T. coronaria exhibited the highest anti-TB activity with minimum inhibitory concentrations (MICs) of 100-200 μg/mL and minimum bactericidal concentration (MBC) of 200 μg/mL. GC-MS phytochemical analysis of these active partitions revealed that majority of the identified compounds belonged to lipophilic fatty acid groups. The active partitions of C. speciosus and T. coronaria exhibited high cidal activity in relation to time, killing more than 99% of the cell population. SEM observations showed that these active plant partitions caused multiple structural changes indicating massive cellular damages.

    CONCLUSIONS: The n-hexane partition of the plant materials exhibited promising in vitro anti-TB activity against M. tuberculosis H37Rv. Their anti-TB activity was supported by their destructive effects on the integrity of the mycobacterial cellular structure.

  14. Hassanpour M, Hassanpour M, Uddin Khandaker M, Rashed Iqbal Faruque M, Alshahrani B, Osman H
    Appl Radiat Isot, 2023 Sep;199:110910.
    PMID: 37379789 DOI: 10.1016/j.apradiso.2023.110910
    Radiation protection is crucial for the safe utilization of ionizing radiation and minimizing the harmful effect upon exposure, hence some standards have been defined by some relevant organizations for the safe uses of radiation. One of the parameters relevant to the calculation of gamma ray shielding is the half-value layer (HVL), which is normally calculated using the knowledge of linear attenuation coefficient (μ). In this research, an attempt has been made to directly calculate HVL without the knowledge of μ via Monte Carlo simulation technique. For this purpose, in the Monte Carlo N-Particle eXtended (MCNPX) code, F1, F5 and Mesh Popul sequences tallies were defined and the optimal structure for the least measurement error was introduced. The MCNPX calculated values showed reasonable agreement with the experimental findings. According to the obtained results, it is suggested that in order to reduce the error of HVL calculations, in exchange for the MCNPX code, the values of the R parameter and the radiation angle of the source should be considered according to the calculations introduced in this plan. Because the results show that by considering the measurement error between 6 and 20%, the code output can be cited in different energy ranges.
  15. Mohamed AH, Noorhisham NA, Yahaya N, Mohamad S, Kamaruzzaman S, Osman H, et al.
    Crit Rev Anal Chem, 2023;53(4):906-927.
    PMID: 34693833 DOI: 10.1080/10408347.2021.1992262
    Despite organophosphorus pesticides (OPPs) benefits in controlling vector-borne diseases and noxious insects, the bioaccumulation and persistence in the soil system may metamorphose into new substances which could pose a serious threat to the ecosystems and human health. The generally low levels of OPPs residues and often the complexity of the soil matrix are the issues that researcher must deal with. Thus, it is essential to isolate and preconcentrate the OPPs from the matrix to reduce interference effects to obtain a reliable detection. Researchers have reported sample preparation techniques as a promising approach to improve analytical measurement of merits including recovery, precision, linearity, limit of detection, and limit of quantification. Under the selected conditions, limits of detection range between 0.001 and 143 ng/mL, and extraction recovery range between 5 and 154% were obtained. This review evaluates the challenges and opportunities, emphasizes the prospects of sampling techniques and various (micro)extraction coupled with chromatographic methods in different soil samples. Based on the finding, the extraction efficiency depended largely on the interaction between OPPs and extraction media. The fate, migration, toxicity impact, sampling procedure, and storage which influenced the sample preparation were comprehensively discussed.
  16. Itas YS, Razali R, Tata S, Kolo M, Osman H, Idris AM, et al.
    Sci Technol Adv Mater, 2023;24(1):2271912.
    PMID: 38024795 DOI: 10.1080/14686996.2023.2271912
    This work investigates the fundamental photocatalytic properties of nitrogen-doped single-walled silicon carbide nanotubes (N-doped SWSiCNTs) for hydrogen evolution for the first time. Investigations of the structural, mechanical, electronic, and optical properties of the studied systems were carried out using popular density functional theory implemented in quantum ESPRESSO and Yambo codes. Analysis of the structural properties revealed high mechanical stability with the 3.6% and 7.4% N-doped SWSiCNT. The calculated band gap of the N-doped SWSiCNT with 3.6% demonstrated a value of 2.56 eV which is within the photocatalytic range of 2.3 eV-2.8 eV. The hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) potentials of the 3.6% N-doped SWSiCNT also showed good agreement with previous theoretical data. The studied material showed the best photocatalytic performance in both parallel and perpendicular directions by absorbing photons in the visible region. Therefore, the observed structural, mechanical, electronic and optical behaviors demonstrated by the 3.6% N-doped SWSiCNT exposed it as a better photocatalyst for hydrogen production under visible light.
  17. Suresh Kumar R, Almansour AI, Arumugam N, Altaf M, Menéndez JC, Kumar RR, et al.
    Molecules, 2016 Jan 29;21(2):165.
    PMID: 26840282 DOI: 10.3390/molecules21020165
    The microwave-assisted three-component reactions of 3,5-bis(E)-arylmethylidene]tetrahydro-4(1H)-pyridinones, acenaphthenequinone and cyclic α-amino acids in an ionic liquid, 1-butyl-3-methylimidazolium bromide, occurred through a domino sequence affording structurally intriguing diazaheptacyclic cage-like compounds in excellent yields.
  18. Miah MH, Khandaker MU, Aminul Islam M, Nur-E-Alam M, Osman H, Ullah MH
    RSC Adv, 2024 Feb 21;14(10):6656-6698.
    PMID: 38390503 DOI: 10.1039/d4ra00433g
    Perovskite materials have attracted significant attention as innovative and efficient X-ray detectors owing to their unique properties compared to traditional X-ray detectors. Herein, chronologically, we present an in-depth analysis of X-ray detection technologies employing organic-inorganic hybrids (OIHs), all-inorganic and lead-free perovskite material-based single crystals (SCs), thin/thick films and wafers. Particularly, this review systematically scrutinizes the advancement of the diverse synthesis methods, structural modifications, and device architectures exploited to enhance the radiation sensing performance. In addition, a critical analysis of the crucial factors affecting the performance of the devices is also provided. Our findings revealed that the improvement from single crystallization techniques dominated the film and wafer growth techniques. The probable reason for this is that SC-based devices display a lower trap density, higher resistivity, large carrier mobility and lifetime compared to film- and wafer-based devices. Ultimately, devices with SCs showed outstanding sensitivity and the lowest detectable dose rate (LDDR). These results are superior to some traditional X-ray detectors such as amorphous selenium and CZT. In addition, the limited performance of film-based devices is attributed to the defect formation in the bulk film, surfaces, and grain boundaries. However, wafer-based devices showed the worst performance because of the formation of voids, which impede the movement of charge carriers. We also observed that by performing structural modification, various research groups achieved high-performance devices together with stability. Finally, by fusing the findings from diverse research works, we provide a valuable resource for researchers in the field of X-ray detection, imaging and materials science. Ultimately, this review will serve as a roadmap for directing the difficulties associated with perovskite materials in X-ray detection and imaging, proposing insights into the recent status, challenges, and promising directions for future research.
  19. Brishty SR, Hossain MJ, Khandaker MU, Faruque MRI, Osman H, Rahman SMA
    Front Pharmacol, 2021;12:762807.
    PMID: 34803707 DOI: 10.3389/fphar.2021.762807
    Nowadays, nitrogenous heterocyclic molecules have attracted a great deal of interest among medicinal chemists. Among these potential heterocyclic drugs, benzimidazole scaffolds are considerably prevalent. Due to their isostructural pharmacophore of naturally occurring active biomolecules, benzimidazole derivatives have significant importance as chemotherapeutic agents in diverse clinical conditions. Researchers have synthesized plenty of benzimidazole derivatives in the last decades, amidst a large share of these compounds exerted excellent bioactivity against many ailments with outstanding bioavailability, safety, and stability profiles. In this comprehensive review, we have summarized the bioactivity of the benzimidazole derivatives reported in recent literature (2012-2021) with their available structure-activity relationship. Compounds bearing benzimidazole nucleus possess broad-spectrum pharmacological properties ranging from common antibacterial effects to the world's most virulent diseases. Several promising therapeutic candidates are undergoing human trials, and some of these are going to be approved for clinical use. However, notable challenges, such as drug resistance, costly and tedious synthetic methods, little structural information of receptors, lack of advanced software, and so on, are still viable to be overcome for further research.
  20. Sofian ZM, Shafee SS, Abdullah JM, Osman H, Razak SA
    Malays J Med Sci, 2014 Dec;21(Spec Issue):6-11.
    PMID: 25941458
    A simple, reliable a 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxy-phenyl)-2-(4-sulfophenyl)-2H-tetrazolium, (MTS) assay was conducted to evaluate the potential cytotoxic effects of levodopa, a "gold standard therapy" for Parkinsonism, and its complex with Hydroxypropyl-β-Cyclodextrin (HP-β-CD) on an astrocyte cell line. The cells were incubated in a range of concentrations from 4.69 to 300 μg/mL levodopa, HP-β-CD or the complex for up to 72 hours. At every 24-hour interval, the optical density (OD), which reflects the number of viable cells, was recorded. In general, linear dose-dependent cytotoxicity profiles were observed for the cells subjected to levodopa or the complex, whereas a slightly triphasic response was observed for the cells exposed to HP-β-CD. A significant difference (P < 0.05) in cytotoxicity was detected between the HP-β-CD-treated group and the levodopa-treated group. In particular, we observed that the cells treated with the complex, even at the highest concentrations (> 200 μg/mL), exhibited improved tolerability in a time-dependent manner, which may indicate the potential ability of HP-β-CD to mask the toxic effects of levodopa via complexation.
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