Displaying publications 141 - 160 of 200 in total

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  1. Amer AAG, Othman N, Sapuan SZ, Alphones A, Salem AA
    PLoS One, 2023;18(12):e0291354.
    PMID: 38127949 DOI: 10.1371/journal.pone.0291354
    This study introduces a metasurface (MS) based electrically small resonator for ambient electromagnetic (EM) energy harvesting. It is an array of novel resonators comprising double-elliptical cylinders. The harvester's input impedance is designed to match free space, allowing incident EM power to be efficiently absorbed and then maximally channelled to a single load through optimally positioned vias. Unlike the previous research works where each array resonator was connected to a single load, in this work, the received power by all array resonators is channelled to a single load maximizing the power efficiency. The performance of the MS unit cell, when treated as an infinite structure, is examined concerning its absorption and harvesting efficiency. The numerical results demonstrate that the MS unit cell can absorb EM power, with near-perfect absorption of 90% in the frequency range of 5.14 GHz to 5.5 GHz under normal incidence and with a fractional bandwidth of 21%. The MS unit cell also achieves higher harvesting efficiency at various incident angles up to 60o. The design and analysis of an array of 4x4 double elliptical cylinder MS resonators integrated with a corporate feed network are also presented. The corporate feed network connects all the array elements to a single load, maximizing harvesting efficiency. The simulation and measurement results reveal an overall radiation to AC efficiency of about 90%, making it a prime candidate for energy harvesting applications.
  2. Zakaria MN, Ensin EG, Awang MA, Salim R, Nik Othman NA, Rashid MFN
    Med J Malaysia, 2023 Dec;78(7):901-906.
    PMID: 38159926
    INTRODUCTION: The sensorineural acuity level (SAL) test was developed as an alternative assessment to estimate bone conduction (BC) thresholds in cases where masking problems occur in pure tone audiometry (PTA). Nevertheless, prior to its clinical application, the respective SAL normative data must be made available. As such, the present study was carried out to establish SAL normative data using an insert earphone and two different commercially available bone transducers. Additionally, to determine the effect of earphone type on SAL test results, it was also of interest to compare the present study's findings with those of a previous study (that used a headphone to derive SAL normative data).

    MATERIALS AND METHODS: In this repeated-measures study, 40 Malaysian adults (aged 19-26 years) with normal hearing bilaterally (based on PTA results) were enrolled. They then underwent the SAL test based on the recommended protocol by Jerger and Tillman (1960). The SAL normative data for each ear were obtained by calculating the differences between air conduction (AC) thresholds in quiet and AC thresholds in noise by means of insert earphone, B71 and B81 bone vibrators.

    RESULTS: The SAL normative values were comparable between the ears (p > 0.05), and the data were pooled for subsequent analyses (n = 80 ears). Relative to B81 bone transducer, B71 bone vibrator produced statistically higher SAL normative data at all frequencies (p < 0.05). The SAL normative values established by the present study were statistically lower than those of the previous study (that utilised headphones) at most of frequencies tested (p < 0.05).

    CONCLUSIONS: The SAL normative data produced by the two bone vibrators were significantly different. The SAL normative values were also affected by the type of earphone used. While conducting the SAL test on Malaysian patients, the information provided by this study can be useful to guide the respective clinicians in choosing the appropriate normative data.

  3. Aziz HA, Othman N, Yusuff MS, Basri DR, Ashaari FA, Adlan MN, et al.
    Environ Int, 2001 May;26(5-6):395-9.
    PMID: 11392757
    This paper discusses heavy metal removal from wastewater by batch study and filtration technique through low-cost coarse media. Batch study has indicated that more than 90% copper (Cu) with concentration up to 50 mg/l could be removed from the solution with limestone quantity above 20 ml (equivalent to 56 g), which indicates the importance of limestone media in the removal process. This indicates that the removal of Cu is influenced by the media and not solely by the pH. Batch experiments using limestone and activated carbon indicate that both limestone and activated carbon had similar metal-removal efficiency (about 95%). Results of the laboratory-scale filtration technique using limestone particles indicated that above 90% removal of Cu was achieved at retention time of 2.31 h, surface-loading rate of 4.07 m3/m2 per day and Cu loading of 0.02 kg/m3 per day. Analyses of the limestone media after filtration indicated that adsorption and absorption processes were among the mechanisms involved in the removal processes. This study indicated that limestone can be used as an alternative to replace activated carbon.
  4. Riyadi FA, Azman NF, Nadia Md Akhir F, Othman N, Hara H
    J Gen Appl Microbiol, 2024 Mar 07;69(5):278-286.
    PMID: 37612074 DOI: 10.2323/jgam.2023.08.003
    Biological pretreatment using microbial enzymes appears to be the most promising pre-treatment technology for the breakdown of recalcitrant lignin structure. This research focuses on the identification and characterization of lignin-depolymerizing enzymes in Bacillus subtilis strain S11Y, previously isolated from palm oil wastes in Malaysia. The draft genome sequences of this highly lignin-depolymerizing strain revealed that the genome lacked any of the well-known dye-decolorizing peroxidase or catalase-peroxidase that are commonly reported to be involved in lignin depolymerization by bacteria, indicating that strain S11Y has distinct sets of potential lignin depolymerization genes. The oxidative stress-related enzymes Cu/Zn type-superoxide dismutase (Sod2) and a heme-containing monofunctional catalase (Kat2) were identified in the genome sequences that are of interest. Their lignin-depolymerizing ability were evaluated by treating Alkali lignin (AL) with each enzyme and their degradation ability were evaluated using gel-permeation chromatography (GPC), ultrahigh-pressure liquid chromatography-mass spectrometry (UHPLC/MS), and gas chromatography-mass spectrometry (GC/MS), which successfully proved lignin depolymerizing ability. Successful evaluation of lignin depolymerizing enzymes can be applicable for lignin pretreatment process in green energy production and generation of valuable chemicals in bio-refinery.
  5. Ng KL, Tan SN, Huan NC, Nasaruddin MZ, Othman N, Rahaman JAA
    Respirol Case Rep, 2024 Mar;12(3):e01333.
    PMID: 38528948 DOI: 10.1002/rcr2.1333
    Multiple myeloma (MM) is characterized by neoplastic proliferation of monoclonal antibody producing plasma cells. In clinical practice, pleural effusion is seen in up to 6% of MM patients, with many causative factors. Nevertheless, true myelomatous pleural effusion, defined as infiltration of the pleura by myeloma cells, is very rare. In this case report, we present two patients with biopsy proven myelomatous pleural effusion. The first patient developed myelomatous pleural effusion as initial presentation while the second patient's pleural effusion occurred during disease relapse. In both cases, prompt diagnosis via medical thoracoscopy (MT) followed by early commencement of myeloma specific chemotherapy led to clinical, biochemical, and radiological resolution and therefore were crucial steps in the management of myelomatous pleural effusion.
  6. Sharma R, Goossens B, Heller R, Rasteiro R, Othman N, Bruford MW, et al.
    Sci Rep, 2018 01 17;8(1):880.
    PMID: 29343863 DOI: 10.1038/s41598-017-17042-5
    The origin of the elephant on the island of Borneo remains elusive. Research has suggested two alternative hypotheses: the Bornean elephant stems either from a recent introduction in the 17th century or from an ancient colonization several hundreds of thousands years ago. Lack of elephant fossils has been interpreted as evidence for a very recent introduction, whereas mtDNA divergence from other Asian elephants has been argued to favor an ancient colonization. We investigated the demographic history of Bornean elephants using full-likelihood and approximate Bayesian computation analyses. Our results are at odds with both the recent and ancient colonization hypotheses, and favour a third intermediate scenario. We find that genetic data favour a scenario in which Bornean elephants experienced a bottleneck during the last glacial period, possibly as a consequence of the colonization of Borneo, and from which it has slowly recovered since. Altogether the data support a natural colonization of Bornean elephants at a time when large terrestrial mammals could colonise from the Sunda shelf when sea levels were much lower. Our results are important not only in understanding the unique history of the colonization of Borneo by elephants, but also for their long-term conservation.
  7. Mohd Nor SNA, Ng BHK, Othman N, Tang IP
    Indian J Otolaryngol Head Neck Surg, 2022 Dec;74(Suppl 3):5478-5481.
    PMID: 36742515 DOI: 10.1007/s12070-021-02803-6
    Pharyngeal lipoma of the upper aero-digestive system is extremely rare. It is typically benign, slow growing and symptoms would depend on its size and location. Surgical intervention is often needed especially for large tumour with impending airway obstruction. Here we present a case of potentially life threatening presentation of pharyngeal lipoma.
  8. Wong WK, Tan ZN, Othman N, Lim BH, Mohamed Z, Olivos Garcia A, et al.
    Clin Vaccine Immunol, 2011 Nov;18(11):1913-7.
    PMID: 21918120 DOI: 10.1128/CVI.05356-11
    Serodiagnosis of amoebiasis remains the preferred method for diagnosis of amoebic liver abscess (ALA). However, the commercially available kits are problematic in areas of endemicity due to the persistently high background antibody titers. Human serum samples (n = 38) from patients with ALA who live in areas of endemicity were collected from Hospital Universiti Sains Malaysia during the period of 2008 to 2010. Western blots using excretory-secretory antigen (ESA) collected from axenically grown Entamoeba histolytica were probed with the above serum samples. Seven antigenic proteins of ESA with various reactivities were identified, i.e., 152 kDa, 131 kDa, 123 kDa, 110 kDa, 100 kDa, 82 kDa, and 76 kDa. However, only the 152-kDa and 110-kDa proteins showed sensitivities above 80% in the Western blot analysis. All the antigenic proteins showed undetectable cross-reactivity when probed with healthy human serum samples (n = 30) and serum samples from other infections (n = 33). From the matrix-assisted laser desorption ionization-two-stage time of flight (MALDI-TOF/TOF) analysis, the proteins were identified as heavy subunits of E. histolytica lectin and E. histolytica pyruvate phosphate dikinase, respectively. Use of the E. histolytica lectin for diagnosis of ALA has been well reported by researchers and is being used in commercialized kits. However, this is the first report on the potential use of pyruvate phosphate dikinase for diagnosis of ALA; thus, this molecule merits further evaluation on its diagnostic value using a larger panel of serum samples.
  9. Al-Ani AHHDA, Othman N, Hassali MA, Ibrahim B
    Malays J Med Sci, 2022 Oct;29(5):17-23.
    PMID: 36474531 DOI: 10.21315/mjms2022.29.5.3
    Sepsis is a medical emergency that involves a systemic immunological response due to an infection, resulting in the end-stage-organs malfunction and death. It is associated with high mortality rate despite a better understanding of the disease pathology and the mechanism involved. This review was designed to summarise the available evidences regarding the adequacy of the empiric antimicrobial therapy (EAMT), its predictors and its impact on the outcomes in intensive care unit (ICU) sepsis patients. Providing an adequate EAMT is considered one of the cornerstones of sepsis management as it has been found to be associated with better survival and is a good predictor for shorter ICU-length-of-stay. In contrast, inadequate EAMT in sepsis patients is associated with poor clinical outcomes including increased mortality and prolonged hospital stay. Evidence from this review suggest that it is important to identify determinants of inadequate EAMT to optimise the antimicrobial therapy provided to sepsis patients. Predictors of inadequate EAMT included co-morbidities (cancer), source and type of infection, higher Acute Physiology and Chronic Health Evaluation (APACHI-II) score and long hospital stay prior to the infection. As EAMT is considered as one of the effective treatment strategies to prevent sepsis associated death, healthcare providers should ensure the adequate antimicrobial therapy is provided for sepsis patients to improve and optimise their management.
  10. Lean SS, Suhaili Z, Ismail S, Rahman NI, Othman N, Abdullah FH, et al.
    ISRN Microbiol, 2014;2014:953417.
    PMID: 25006521 DOI: 10.1155/2014/953417
    Nosocomial infection caused by Acinetobacter baumannii is of great concern due to its increasing resistance to most antimicrobials. In this study, 54 nonrepeat isolates of A. baumannii from the main tertiary hospital in Terengganu, Malaysia, were analyzed for their antibiograms and genotypes. Out of the 54 isolates, 39 (72.2%) were multidrug resistant (MDR) and resistant to carbapenems whereas 14 (25.9%) were categorized as extensive drug resistant (XDR) with additional resistance to polymyxin B, the drug of "last resort." Pulsed-field gel electrophoresis analyses showed that the polymyxin-resistant isolates were genetically diverse while the carbapenem-resistant isolates were clonally related. The 14 XDR isolates were further investigated for mutations in genes known to mediate polymyxin resistance, namely, pmrCAB, and the lipopolysaccharide biosynthesis genes, lpxA, lpxC, lpxD, and lpsB. All 14 isolates had a P102H mutation in pmrA with no mutation detected in pmrC and pmrB. No mutation was detected in lpxA but each polymyxin-resistant isolate had 2-4 amino acid substitutions in lpxD and 1-2 substitutions in lpxC. Eight resistant isolates also displayed a unique H181Y mutation in lpsB. The extent of polymyxin resistance is of concern and the novel mutations discovered here warrant further investigations.
  11. Othman N, Pan L, Mejin M, Voong JC, Chai HB, Pannell CM, et al.
    J Nat Prod, 2016 Apr 22;79(4):784-91.
    PMID: 26974604 DOI: 10.1021/acs.jnatprod.5b00810
    Four new 2,3-secodammarane triterpenoids, stellatonins A-D (3-6), together with a new 3,4-secodammarane triterpenoid, stellatonin E (7), and the known silvestrol (1), 5‴-episilvestrol (2), and β-sitosterol, were isolated from a methanol extract of the stems of Aglaia stellatopilosa through bioassay-guided fractionation. The structures of the new compounds were elucidated using spectroscopic and chemical methods. The compounds were evaluated for their cytotoxic activity against three human cancer cell lines and for their antimicrobial activity using a microtiter plate assay against a panel of Gram-positive and Gram-negative bacteria and fungi.
  12. Mamat CF, Jamshed SQ, El Syed T, Khan TM, Othman N, Al-Shami AK, et al.
    J Pharm Bioallied Sci, 2015 Jul-Sep;7(3):181-7.
    PMID: 26229351 DOI: 10.4103/0975-7406.160011
    This detailed review analyzed the previously published studies related to the prevalence of psychotropic substances use, associated factors, and the misuse of the psychotropics among students. A comprehensive literature search covering six databases was performed. References from published articles and reports were extracted. This helped in identifying the available information on the use of psychotropic drugs. A total of 16 articles were included in this review. There is an upsurge of using psychotropics with the preceding years. More students are exposed to the risk of using psychotropic substances due to the multiple factors like stress, increased academic workload, etc. The misuse is found to be common with prescribed psychotropic substances. Students need to be aware of the bad outcomes of using psychotropic substances. Participation of every stakeholder to curb this menace needs to be emphasized. More extensive studies are required to know about the increasing prevalence, factors, and misuse of psychotropics.
  13. Mat Yusoff Y, Abu Seman Z, Othman N, Kamaluddin NR, Esa E, Zulkiply NA, et al.
    Asian Pac J Cancer Prev, 2018 Dec 25;19(12):3317-3320.
    PMID: 30583336
    Objective: Chronic Myeloid Leukemia (CML) is caused by a reciprocal translocation between chromosomes 9
    and 22, t(9;22) (q34;q11) which encodes for the BCR-ABL fusion protein. Discovery of Imatinib Mesylate (IM) as
    first line therapy has brought tremendous improvement in the management of CML. However, emergence of point
    mutations within the BCR-ABL gene particularly T315I mutation, affects a common BCR-ABL kinase contact residue
    which impairs drug binding thus contribute to treatment resistance. This study aims to investigate the BCR-ABL T315I
    mutation in Malaysian patients with CML. Methods: A total of 285 patients diagnosed with CML were included in this
    study. Mutation detection was performed using qualitative real-time PCR (qPCR). Results: Fifteen out of 285 samples
    (5.26%) were positive for T315I mutations after amplification with real-time PCR assay. From the total number of
    positive samples, six patients were in accelerated phase (AP), four in chronic phase (CP) and five in blast crisis (BC).
    Conclusion: Mutation testing is recommended for choosing various tyrosine kinase inhibitors (TKIs) to optimize
    outcomes for both cases of treatment failure or suboptimal response to imatinib. Therefore, detection of T315I mutation
    in CML patients are clinically useful in the selection of appropriate treatment strategies to prevent disease progression.
  14. Sha'arani S, Hara H, Araie H, Suzuki I, Mohd Noor MJM, Akhir FNM, et al.
    J Gen Appl Microbiol, 2019 Sep 14;65(4):173-179.
    PMID: 30686798 DOI: 10.2323/jgam.2018.08.003
    This study gives the first picture of whole RNA-Sequencing analysis of a PCB-degrading microbe, Rhodococcus jostii RHA1. Genes that were highly expressed in biphenyl-grown cells, compared with pyruvate-grown cells, were chosen based on the Reads Per Kilobase Million (RPKM) value and were summarized based on the criteria of RPKM ≥100 and fold change ≥2.0. Consequently, 266 total genes were identified as genes expressed particularly for the degradation of biphenyl. After comparison with previous microarray data that identified highly-expressed genes, based on a fold change ≥2.0 and p-value ≤0.05, 62 highly-expressed genes from biphenyl-grown cells were determined from both analytical platforms. As these 62 genes involve known PCB degradation genes, such as bph, etb, and ebd, the genes identified in this study can be considered as essential genes for PCB/biphenyl degradation. In the 62 genes, eleven genes encoding hypothetical proteins were highly expressed in the biphenyl-grown cells. Meanwhile, we identified several highly-expressed unannotated DNA regions on the opposite strand. In order to verify the encoded proteins, two regions were cloned into an expression vector. A protein was successfully obtained from one region at approximately 25 kDa from the unannotated strand. Thus, the genome sequence with transcriptomic analysis gives new insight, considering re-annotation of the genome of R. jostii RHA1, and provides a clearer picture of PCB/biphenyl degradation in this strain.
  15. Mohd Mohsi NF, Apandi A, Megat Mohd Noor MJ, Md Akhir FN, Sugiura N, Utsumi M, et al.
    J Gen Appl Microbiol, 2020 Apr 13;66(1):8-14.
    PMID: 31281138 DOI: 10.2323/jgam.2019.04.001
    Prazosin (PRZ), a drug used to treat hypertensive patients, is an emergent contaminant in water systems. PRZ is an alpha-adrenergic receptor blocker used to treat anxiety, and is believed to reach the environment through human excretion, irresponsible disposal of unused medicine, and waste products from manufacturing plants. The purpose of this research was to isolate and characterize potential microbes for PRZ biodegradation and to identify the degradation pathway. After screening, isolated strain STP3 showed a capability for PRZ degradation and was chosen for further analysis. Resting cell assays with PRZ were conducted to identify the intermediate metabolites formed from biodegradation by Fourier transform ion cyclotron resonance mass spectrometer (FT-ICR MS) analysis. Two metabolites degraded from PRZ by STP3 were successfully found, and as these metabolites are derived from the main structure of PRZ, their presence proved PRZ degradation. Draft genome sequencing analysis of STP3 was performed to identify potential enzymes for PRZ biodegradation based on the metabolites found.
  16. Abu N, Othman N, Ab Razak NS, Bakarurraini NAAR, Nasir SN, Soh JEC, et al.
    Front Cell Dev Biol, 2020;8:564648.
    PMID: 33324632 DOI: 10.3389/fcell.2020.564648
    Colorectal cancer (CRC) is one of the most widely diagnosed cancers worldwide. It has been shown that the body-mass index (BMI) of the patients could influence the tumor microenvironment, treatment response, and overall survival rates. Nevertheless, the mechanism on how BMI affects the tumorigenesis process, particularly the tumor microenvironment is still elusive. Herein, we postulate that extracellular vesicles (EVs) from CRC patients and non-CRC volunteers with different BMI could affect immune cells differently, in CD8 T cells particularly. We isolated the EVs from the archived serum of CRC patients with high and low BMI, as well as healthy controls with similar BMI status. The EVs were further characterized via electron microscopy, western blot and dynamic light scattering. Then, functional analysis was performed on CD8 T cells including apoptosis, cell proliferation, gene expression profiling and cytokine release upon co-incubation with the different EVs. Our results suggest that CRC-derived EVs were able to regulate the CD8 T cells. In some assays, low BMI EVs were functionally different than high BMI EVs. This study highlights the possible difference in the regulatory mechanism of cancer patients-derived EVs, especially on CD8 T cells.
  17. Azman NF, Megat Mohd Noor MJ, Md Akhir FN, Ang MY, Hashim H, Othman N, et al.
    Bioresour Technol, 2019 May;279:174-180.
    PMID: 30721818 DOI: 10.1016/j.biortech.2019.01.122
    Previous studies on screening of lignin-degrading bacteria mainly focused on the ligninolytic ability of the isolated bacteria for the utilization of lignin monomers. In this study, we focused on the depolymerization of alkali lignin to prove the ability of the isolated thermophilic bacterial strains to utilize and depolymerize more than a monomer of alkali lignin within 7 days of incubation. Indigenous thermophilic bacterial isolates from the palm oil plantation were used to evaluate the depolymerization and utilization of alkali lignin. The confirmation of the bacterium-mediated depolymerization of oil palm empty fruit bunch was achieved through the removal of silica bodies, as observed with scanning electron microscopy. Stenotrophomonas sp. S2 and Bacillus subtilis S11Y were able to reduce approximately 50% and 20% of alkali lignin at 7 days of incubation without the requirement for additional carbon sources.
  18. Jones SU, Chua KH, Chew CH, Yeo CC, Abdullah FH, Othman N, et al.
    PeerJ, 2021;9:e11195.
    PMID: 33889447 DOI: 10.7717/peerj.11195
    Background: Staphylococcus aureus is one of the important pathogens causing nosocomial infection. spa typing allows identification of S. aureus clones in hospital isolates and is useful for epidemiological studies and nosocomial infection control. This study aims to investigate the spa types in Malaysian S. aureus isolates obtained from various clinical specimens.

    Method: A total of 89 methicillin-resistant S. aureus (MRSA) [pus (n = 55), blood (n = 27), respiratory (n = 5), eye (n = 2)] isolates and 109 methicillin-susceptible S. aureus (MSSA) [pus (n = 79), blood (n = 24), respiratory (n = 3), eye (n = 2) and urine (n = 1)] isolates were subjected to spa typing with sequences analysed using BioNumerics version 7.

    Results: The spa sequence was successfully amplified from 77.8% of the strains (154/198) and 47 known spa types were detected. The distribution of known spa types in MRSA (36.2%, 17/47) was less diverse than in MSSA (70.2%, 33/47). The most predominant spa types were t032 (50%) in MRSA, and t127 (19%) and t091 (16.7%) in MSSA, respectively. spa type t091 in MSSA was significantly associated with skin and soft tissue infections (p = 0.0199).

    Conclusion: The previously uncommon spa type t032 was detected in the Malaysian MRSA strains, which also corresponded to the most common spa type in Europe and Australia, and has replaced the dominant spa type t037 which was reported in Malaysia in 2010.

  19. Abd Wahid MA, Megat Mohd Noor MJ, Goto M, Sugiura N, Othman N, Zakaria Z, et al.
    Biosci Biotechnol Biochem, 2017 Aug;81(8):1642-1649.
    PMID: 28585494 DOI: 10.1080/09168451.2017.1329617
    The natural coagulant Moringa oleifera lectin (MoL) as cationic protein is a promising candidate in coagulation process of water treatment plant. Introducing the gene encoding MoL into a host, Pichia pastoris, to secrete soluble recombinant protein is assessed in this study. Initial screening using PCR confirmed the insertion of MoL gene, and SDS-PAGE analysis detected the MoL protein at 8 kDa. Cultured optimization showed the highest MoL protein at 520 mg/L was observed at 28 °C for 144 h of culturing by induction in 1% methanol. Approximately, 0.40 mg/mL of recombinant MoL protein showed 95 ± 2% turbidity removal of 1% kaolin suspension. In 0.1% kaolin suspension, the concentration of MoL at 10 μg/mL exhibits the highest turbidity reduction at 68 ± 1%. Thus, recombinant MoL protein from P. pastoris is an effective coagulant for water treatment.
  20. Faisal UH, Sabri NSA, Yusof N, Tahir AA, Said NNM, Riyadi FA, et al.
    Microbiol Resour Announc, 2021 May 13;10(19).
    PMID: 33986086 DOI: 10.1128/MRA.00259-21
    We report the draft genome sequence of Agrobacterium sp. strain S2, isolated from a decaying oil palm empty fruit bunch (OPEFB) in Negeri Sembilan, Malaysia, which yields potential genes encoding lignin degradation enzymes. This genome of 9,722,071 bp exhibited 58.9% GC content, 10,416 coding genes, and 12 RNAs.
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