Displaying publications 101 - 120 of 1043 in total

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  1. Abbas AA, Guo X, Tan WH, Jalab HA
    J Med Syst, 2014 Aug;38(8):80.
    PMID: 24957396 DOI: 10.1007/s10916-014-0080-7
    In a computerized image analysis environment, the irregularity of a lesion border has been used to differentiate between malignant melanoma and other pigmented skin lesions. The accuracy of the automated lesion border detection is a significant step towards accurate classification at a later stage. In this paper, we propose the use of a combined Spline and B-spline in order to enhance the quality of dermoscopic images before segmentation. In this paper, morphological operations and median filter were used first to remove noise from the original image during pre-processing. Then we proceeded to adjust image RGB values to the optimal color channel (green channel). The combined Spline and B-spline method was subsequently adopted to enhance the image before segmentation. The lesion segmentation was completed based on threshold value empirically obtained using the optimal color channel. Finally, morphological operations were utilized to merge the smaller regions with the main lesion region. Improvement on the average segmentation accuracy was observed in the experimental results conducted on 70 dermoscopic images. The average accuracy of segmentation achieved in this paper was 97.21 % (where, the average sensitivity and specificity were 94 % and 98.05 % respectively).
    Matched MeSH terms: Sensitivity and Specificity
  2. Wong YP, Chua KH, Thong KL
    J Microbiol Methods, 2014 Dec;107:133-7.
    PMID: 25307691
    Nosocomial infections are a major public health concern worldwide. Early and accurate identification of nosocomial pathogens which are often multidrug resistant is crucial for prompt treatment. Hence, an alternative real-time polymerase chain reaction coupled with high resolution melting-curve analysis (HRMA) was developed for identification of five nosocomial bacteria. This assay targets species-specific regions of each nosocomial bacteria and produced five distinct melt curves with each representing a particular bacterial species. The melting curves were characterized by peaks of 78.8 ± 0.2 °C for Acinetobacter baumannii, 82.7 ± 0.2 °C for Escherichia coli, 86.3 ± 0.3 °C for Klebsiella pneumoniae, 88.8 ± 0.2 °C for Pseudomonas aeruginosa and 74.6 ± 02 °C for methicillin-resistant Staphylococcus aureus. The assay was able to specifically detect the five bacterial species with an overall detection limit of 2 × 10(-2) ng/μL. In conclusion, the HRM assay developed is a simple and rapid method for identification of the selected nosocomial pathogens.
    Matched MeSH terms: Sensitivity and Specificity
  3. Tata MD, Gurunathan R, Palayan K
    Ann Gastroenterol, 2014;27(1):34-41.
    PMID: 24714557
    BACKGROUND: Gastric cancer is notably one of the leading causes of cancer-related death in the world. In Malaysia, these patients present in the advanced stage, thus narrowing the treatment options and making the surgery nearly impossible for successful curative resection. Failure to identify high-risk patients and delay in diagnostic endoscope procedure contributed to the delay in diagnosis. The aim of the study was to develop and validate a scoring system (MARK's Quadrant) which can identify symptomatic patients who are at risk for gastric cancer.

    METHODS: A 3-phase approach was undertaken: Phase 1: development of the weighted scoring system; Phase 2: estimating positive predicting value of MARK's Quadrant; and Phase 3: a) testing the validity of MARK's Quadrant in an open-access endoscope system; and b) comparing its usefulness compared to conventional referral system.

    RESULTS: In phases 1 and 2, MARK's Quadrant with weighted symptoms was developed. The sensitivity of MARK's Quadrant is 88% and the specificity is 45.5% to detect cancerous and precancerous lesions of gastric. This was confirmed by the prospective data from phase 3 of this study where the diagnostic yield of MARK's Quadrant to detect any pathological lesion was 95.2%. This score has a high accuracy efficiency of 75%, hence comparing to routine referral system it has an odds ratio (95%CI) of 10.98 (4.63-26.00), 6.71 (4.46-10.09) and 0.95 (0.06-0.15) (P<0.001 respectively) for cancer, precancerous lesion and benign lesion diagnosis respectively.

    CONCLUSION: MARK's Quadrant is a useful tool to detect early gastric cancer among symptomatic patients in a low incidence region.

    Matched MeSH terms: Sensitivity and Specificity
  4. Alashrah S, Kandaiya S, Lum LS, Cheng SK
    Z Med Phys, 2013 Dec;23(4):270-8.
    PMID: 24113373 DOI: 10.1016/j.zemedi.2013.09.001
    One of the factors which influence the spatial resolution of a 2D detector array is the size of the single detector, another the transport of the secondary electrons from the walls into the measuring volume. In this study, the single ion chamber dose response function of an I'mRT MatriXX array was determined by comparison between slit beam dose profiles measured with the array and with EBT2 radiochromic film in a solid water-equivalent phantom at a shallow depth of 0.5cm and at a depth of 5cm beyond the depth dose maximum for a 6 MV photon beam. The dose response functions were obtained using two methods, the best fit method and the deconvolution method. At the shallow depth, a Lorentz function and at 5cm depth a Gaussian function, both with the same FWHM of 7.4mm within limits of uncertainty, were identified as the best suited dose response functions of the 4.5mm diameter single array chamber. These dose response functions were then tested on various dose profiles whose true shape had been determined with EBT2 film and with the IC03 ionization chamber. By convolving these with the Lorentz kernel (at shallow depth) and the Gaussian kernel (at 5cm depth) the signal profiles measured with the I'mRT MatriXX array were closely approximated. Thus, the convolution of TPS-calculated dose profiles with these dose response functions can minimize the differences between calculation and measurement which occur due to the limited spatial resolution of the I'mRT MatriXX detector.
    Matched MeSH terms: Sensitivity and Specificity
  5. Ajiya M, Mahdi MA, Al-Mansoori MH, Hitam S, Mokhtar M
    Opt Express, 2009 Apr 13;17(8):5944-52.
    PMID: 19365413
    We experimentally demonstrate a simple widely tunable multiwavelength Brillouin/Erbium fiber laser that can be tuned over the entire C-band, thereby greatly improving the tuning range limitation faced by the previous Brillouin-erbium fiber laser architectures. Tuning range of 39 nm from 1527 nm to 1566 nm, which is only limited by the amplification bandwidth of the erbium gain was successfully achieved. At Brillouin pump wavelength of 1550 nm and 1480 nm laser pump and Brillouin pump powers of 130 mW and 2 mW respectively, all the generated output channels have peak power above 0 dBm, with the first output channel having a peak power of 8.52 dBm. The experimental set up that consists of only 4 optical components, is simple, devoid of the complex structure employed previously to enhance the tunability and feedback mechanism normally associated with multiwavelength Brillouin-erbium fiber laser sources. The generated output channels are stable, rigidly separated by 10 GHz (0.08 nm).
    Matched MeSH terms: Sensitivity and Specificity
  6. Samat SB, Evans CJ, Kadni T, Dolah MT
    Radiat Prot Dosimetry, 2009 Feb;133(3):186-91.
    PMID: 19299478 DOI: 10.1093/rpd/ncp035
    During the years 1985-2008, the Secondary Standards Dosimetry Laboratory of Malaysia (SSDL Malaysia) has participated 37 times in the IAEA/WHO intercomparison programmes. This paper reports an analysis of the intercomparison data and demonstrates that the quality of the SSDL calibration service is well within the limits required by IAEA.
    Matched MeSH terms: Sensitivity and Specificity
  7. Tan AK, Mallika P. S., Aziz S, Asokumaran T, Intan G, Faridah HA
    Malays Fam Physician, 2010;5(2):83-90.
    PMID: 25606193 MyJurnal
    OBJECTIVE: To determine the sensitivity and specificity of the conventional direct ophthalmoscope and the PanOptic ophthalmoscope in the detection of sight threatening retinopathy, as well as the "Ease of Use" of these equipments.
    METHODS: 200 diabetics, newly referred from primary health physicians were examined. Fundus examinations were performed with pupil dilatation in a dark room. The examinations were performed by a single investigator using the PanOptic ophthalmoscope, the conventional direct ophthalmoscope and slit lamp biomicroscopy.
    RESULTS: The overall sensitivity in detecting sight threatening retinopathy using the conventional direct ophthalmoscope was 73.2% (95% CI: 57.1-85.8%), specificity 93.7% (95% CI: 88.7-96.9%). For PanOptic ophthalmoscope, the overall sensitivity in detecting sight threatening retinopathy was 58.5% (95% CI: 42.1-73.7%), specificity 93.7% (95% CI: 88.7-96.9%). The conventional direct ophthalmoscope was 1.38 times (95% CI: 1.17-1.61 times) as easy to use compared to the PanOptic ophthalmoscope.
    CONCLUSION: The PanOptic ophthalmoscope is not superior to the conventional direct ophthalmoscope for the screening of Sight Threatening Retinopathy.
    KEYWORDS: PanOptic ophthalmoscope; conventional direct ophthalmoscope; sight threatening retinopathy
    Study site: Ophthalmology clinic, Sarawak General Hospital, Kuching, Sarawak, Malaysia
    Matched MeSH terms: Sensitivity and Specificity
  8. Mahdi MA, Sheih SJ, Adikan FR
    Opt Express, 2009 Jun 08;17(12):10069-75.
    PMID: 19506658
    We demonstrate a simplified algorithm to manifest the contribution of amplified spontaneous emission in variable gain-flattened Erbium-doped fiber amplifier (EDFA). The detected signal power at the input and output ports of EDFA comprises of both signal and noise. The generated amplified spontaneous emission from EDFA cannot be differentiated by photodetector which leads to underestimation of the targeted gain value. This gain penalty must be taken into consideration in order to obtain the accurate gain level. By taking the average gain penalty within the dynamic gain range, the targeted output power is set higher than the desired level. Thus, the errors are significantly reduced to less than 0.15 dB from 15 dB to 30 dB desired gain values.
    Matched MeSH terms: Sensitivity and Specificity
  9. Chong H, Cheah SH, Ragavan M, Johgalingam VT
    J Immunoassay Immunochem, 2009;30(2):166-79.
    PMID: 19330642 DOI: 10.1080/15321810902782863
    An indirect enzyme immunoassay for the measurement of total 17alpha-hydroxyprogesterone (17OHP) in serum using monoclonal antibodies generated in our laboratory was developed. Here, (a) instead of extraction with solvents, serum was heated to free protein-bound 17OHP and assay was performed at pH 9.6, (b) to ensure uniform assay conditions for both standards and samples, buffer for standards contained charcoal-stripped pre-heated pooled cord serum. Assays were done in 96-well EIA microplates pre-coated with 17alpha-hydroxyprogesterone-3-(o-carboxymethyl)oxime: bovine serum albumin. Secondary antibody was horseradish peroxidase-linked sheep anti-mouse IgG polyclonal antibody. The method was accurate and suitable for screening for congenital adrenal hyperplasia.
    Matched MeSH terms: Sensitivity and Specificity
  10. Helvaci MR, Ozer C, Kaya H, Yalcin A
    Med J Malaysia, 2008 Jun;63(2):122-4.
    PMID: 18942297
    We tried to understand whether there are significant cut off values simply determining body mass index (BMI). The study was performed in Internal Medicine Polyclinics on consecutive check up patients aged between 15 and 70 years to see possible consequences of excess weight on health and to avoid debility induced weight loss in elders. Insulin using diabetics and patients with devastating illnesses were excluded to avoid their possible effects on weight. Cases were subdivided into three groups according to their body weights as under 65, between 65 and 85, and above 85 kg groups and prevalences of underweight, normal weight, overweight, and obesity were determined. Sensitivity, specificity, and positive and negative predictive values of body weights to determine BMI were calculated. The study included 954 cases (566 females). Sensitivity of 65 kg as a cut off value to detect normal weight was 61.0%, specificity 94.3%, positive predictive value 82.9%, and negative predictive value was 97.6%. Similarly, sensitivity, specificity, and positive and negative predictive values of 65 and 85 kg to detect overweight cases were 71.5%, 63.3%, 56.2%, and 77.1% respectively. So both values were statistically significant to detect normal weight, overweight and obese individuals (p = 0.000 for both). Although BMI is probably a more valuable parameter to show weight status, the cut off values of 65 and 85 kg, as an easier way, have significant places, too.
    Matched MeSH terms: Sensitivity and Specificity
  11. Chew FN, Tan WS, Ling TC, Tan CS, Tey BT
    Anal Biochem, 2009 Jan 15;384(2):353-5.
    PMID: 18952038 DOI: 10.1016/j.ab.2008.10.010
    Green fluorescent protein (GFP) is a versatile reporter protein and has been widely used in biological research. However, its quantitation requires expensive equipment such as a spectrofluorometer. In the current study, a gel documentation imaging system using a native polyacrylamide gel for the quantitation of GFP was developed. The assay was evaluated for its precision, linearity, reproducibility, and sensitivity in the presence of Escherichia coli cells and was compared with the spectrofluorometric method. Using this newly established, gel-based imaging technique; the amount of GFP can be quantified accurately.
    Matched MeSH terms: Sensitivity and Specificity
  12. Abdullah MZ, Yin W, Bilal M, Armitage DW, Mackin R, Peyton AJ
    Rev Sci Instrum, 2007 Aug;78(8):084703.
    PMID: 17764343
    This article addresses time-domain ultrawide band (UWB) electromagnetic tomography for reconstructing the unknown spatial characteristic of an object from observations of the arrivals of short electromagnetic (EM) pulses. Here, the determination of the first peak arrival of the EM traces constitutes the forward problem, and the inverse problem aims to reconstruct the EM property distribution of the media. In this article, the finite-difference time-domain method implementing a perfectly matched layer is used to solve the forward problem from which the system sensitivity maps are determined. Image reconstruction is based on the combination of a linearized update and regularized Landweber minimization algorithm. Experimental data from a laboratory UWB system using targets of different contrasts, sizes, and shapes in an aqueous media are presented. The results show that this technique can accurately detect and locate unknown targets in spite of the presence of significant levels of noise in the data.
    Matched MeSH terms: Sensitivity and Specificity
  13. Francis A, Aiyar S, Yean CY, Naing L, Ravichandran M
    Diagn Microbiol Infect Dis, 2006 Jun;55(2):95-9.
    PMID: 16626918
    Isolation and culture of Burkholderia pseudomallei remains the main stay in the diagnosis of melioidosis. Thus, the search for selective and differential media for B. pseudomallei has been ongoing. A number of such media have been reported with varying efficacy. Ashdown medium is the most established selective medium for the isolation of B. pseudomallei. There are no reports of differential media differentiating B. pseudomallei from Burkholderia cepacia. This report documents such a selective and differentiating medium for B. pseudomallei. Of a total of 1042 clinical specimens containing mixed flora and gram-negative isolates that were tested on this medium, 16 of the specimens yielded B. pseudomallei. The isolation rate was found to be 1.5%. This medium was found to be simple and inexpensive, can be made by small laboratories, and called as Francis medium. Based on the colony morphology and color, a preliminary report can be made within 18-24 h for the presence of B. pseudomallei. Our study showed that this medium had an overall sensitivity of 78.4% with a specificity of 92.2%. The use of this medium as an early diagnostic tool will help to reduce mortality and morbidity of melioidosis patients.
    Matched MeSH terms: Sensitivity and Specificity
  14. Yadav H, Lee N
    Med J Malaysia, 2013;68(1):44-7.
    PMID: 23466766 MyJurnal
    This study examines the association between maternal factors and low birth weight among newborns at a tertiary hospital in Malaysia. This was a cross-sectional study where mothers were followed through from first booking till delivery. There were 666 mothers who delivered from May 2007 to March 2008. Infants' birth weight were compared with maternal age, pre-pregnancy BMI, fathers BMI, parity, ethnicity, per capita monthly income, and maternal blood pressure during pregnancy. A multiple logistic regressions was used to determine the relationship of maternal factors and low birth weight, while the ROC curve was constructed to assess the sensitivity and specificity of the predictive model. Among the significant risk factors of low birth weight were older age (35 years and above), low pre-pregnancy BMI (<20 kg/m2), parity of 4 and above, Indian origin, economically under privileged, and low and high blood pressure. Blood pressure during pregnancy was an important risk factor for LBW, by using this parameter alone the risk of LBW could be predicted with a sensitivity rate of 70% and a specificity rate of 70%. The sensitivity and specificity was further improved to 80% and 75% percent respectively when other factors like maternal factors such as maternal age, pre-pregnancy BMI, ethnicity, and per capita monthly income were included in the analysis.
    Matched MeSH terms: Sensitivity and Specificity
  15. Lee KF, Abdul Rahim A, Raja Azmi MN, Wan Hazabbah WH, Embong Z, Noramazlan R, et al.
    Med J Malaysia, 2013;68(1):39-43.
    PMID: 23466765 MyJurnal
    RetCam is an excellent screening tool for the detection of retinopathy of prematurity (ROP). However, affordability is a barrier when adopting the use of RetCam in developing countries. We aimed to describe different stages of ROP using ultrasonographic B-scan and to evaluate the association between funduscopic examinations and ultrasonographic B-scan findings in premature neonates with ROP in Malaysia. A descriptive cross sectional study was conducted in 90 eyes of 47 premature neonates with different stages of ROP in three tertiary hospitals in Malaysia. Experienced ophthalmologists performed detailed funduscopic examinations using binocular indirect ophthalmoscopy (BIO). A masked examiner performed a 10 MHz ultrasonographic B-scan evaluation with 12 meridian position images within 48 hours of clinical diagnosis. Data from the clinical examination and ultrasonographic findings were collected and analysed. We recruited 37 eyes (41.1%) with stage 1 ROP, 29 eyes (32.3%) with stage 2, 18 eyes (20.0%) with stage 3, and 3 eyes (3.3%) with stages 4 and 5 based on the clinical assessment. Ultrasonography correctly identified 3 (8.1%) stage 1 eyes, 17 (58.6%) stage 2 eyes, 13 (72.2%) stage 3 eyes, and 3 each (100%) of the stage 4 and 5 eyes. There was a significant association between the funduscopic signs and the ultrasound findings for stage 2 ROP and above (Fisher's exact test, p <0.001). In conclusion, all stages of ROP were detected and described with a 10 MHz ultrasonic B-scan system. A significant association was observed between funduscopic signs and ultrasonographic findings in premature Malaysian neonates with stage 2 ROP and above.
    Matched MeSH terms: Sensitivity and Specificity
  16. Menon DK
    Twin Res Hum Genet, 2005 Jun;8(3):259-61.
    PMID: 15989753
    The aim of this study was to determine the accuracy of sonographic chorionicity determination in the largest sample of twin pregnancies to date. We retrospectively analyzed 463 twin pregnancies delivered over a 6-year period to determine in each case what the antenatal sonographic prediction of chorionicity was, and then what the subsequent post partum pathological diagnosis of chorionicity was. Out of 436 twin pregnancies, 428 were correctly diagnosed for chorionicity as confirmed by pathology reports. Sonography as a screening tool for monochorionic twin pregnancies has a sensitivity of 100%, a specificity of 97.9% and a predictive value positive of 88.2%. Transvaginal scanning in the first trimester determined twin chorionicity with a sensitivity and a specificity of 100%. This study has confirmed in the largest sample to date that sonographic chorionicity determination is best done in the first trimester using vaginal scans, where it has 100% accuracy.
    Matched MeSH terms: Sensitivity and Specificity
  17. Rohaizak M, Munchar MJ, Meah FA, Jasmi AY
    Asian J Surg, 2005 Apr;28(2):82-5.
    PMID: 15851358
    Intraoperative identification of parathyroid tissue is crucial during parathyroid surgery. Frozen section is the most common tool, but is time-consuming and expensive. Scrape cytology is a modification of imprint cytology that provides rapid and cheap intraoperative identification of parathyroid tissue, but its reliability remains controversial. We assessed the sensitivity and specificity of scrape cytology in the intraoperative identification of parathyroid tissue.
    Matched MeSH terms: Sensitivity and Specificity
  18. Faizah MZ, Hamzaini AH, Kanaheswari Y, Dayang A AA, Zulfiqar MA
    Med J Malaysia, 2015 Oct;70(5):269-72.
    PMID: 26556113 MyJurnal
    OBJECTIVE: Contrast-enhanced ultrasound has become increasingly utilised as an alternative imaging modality for the diagnosis of vesicoureteric reflux (VUR) in paediatric patients. The study objective is to evaluate the efficacy of contrast enhanced Voiding Urosonography (ce-VUS) compared with fluoroscopic micturating cystourethrography (MCU) in the detection of VUR.
    METHODS: This prospective study was carried out between July 2011 and January 2013 on paediatric patients who underwent MCU. All consented patients would undergo ce- VUS prior to MCU. We documented the epidemiology details, the number of Kidney-Ureter (K-U) unit studied, baseline renal and bladder sonogram, as well as presence of VUR on ce-VUR. The technique for ce-VUS was standardized using normal saline to fill the bladder prior to administration of SonoVue® (2.5 ml) to assess the kidney-ureter (K-U) unit. Dedicated contrast detection software was used to discern the presence of microbubbles in the pelvicaliceal system (PCS). The findings were then compared with MCU.
    RESULTS: 27 paediatric patients were involved in the study [17 males (63%) and 10 females (37%)] involving 55 K-U units (one patient had a complete duplex system). MCU detected VUR in 10 K-U units while ce-VUS detected VUR in 8 out of the 10 K-U units. There were 2 false negative cases (both Grade 1) with ce-VUS. The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of ce-VUS were 80%, 98%, 95%, 89% and 96%, respectively.
    CONCLUSION: ce-VUS is a sensitive and specific radiation-free alternative for the detection of VUR in the paediatric population.
    Matched MeSH terms: Sensitivity and Specificity
  19. Lau YL, Lai MY, Teoh BT, Abd-Jamil J, Johari J, Sam SS, et al.
    PLoS One, 2015;10(9):e0138694.
    PMID: 26384248 DOI: 10.1371/journal.pone.0138694
    Dengue is usually diagnosed by isolation of the virus, serology or molecular diagnostic methods. Several commercial kits for the diagnosis of dengue are existing, but concerns have arisen regarding to the affordability and performance characteristics of these kits. Hence, the loop-mediated isothermal amplification (LAMP) is potentially ideal to be used especially in resource limited environments. Serum was collected from healthy donors and patients diagnosed with dengue infection. RNA extracted from the serum samples were tested by reverse-transcription-LAMP assay developed based on 3'-NCR gene sequences for DENV 1-4. Results were interpreted by a turbidity meter in real time or visually at the end of the assay. Sensitivity and specificity of RT-LAMP results were calculated and compared to qRT-PCR and ELISA. RT-LAMP is highly sensitive with the detection limit of 10 RNA copies for all serotypes. Dengue virus RNA was detected in all positive samples using RT-LAMP and none of the negative samples within 30-45 minutes. With continuing efforts in the optimization of this assay, RT-LAMP may provide a simple and reliable test for detecting DENV in areas where dengue is prevalent.
    Matched MeSH terms: Sensitivity and Specificity
  20. Kanagasingam S, Hussaini HM, Soo I, Baharin S, Ashar A, Patel S
    Int Endod J, 2017 May;50(5):427-436.
    PMID: 27063356 DOI: 10.1111/iej.12651
    AIM: To compare the accuracy of film and digital periapical radiography (PR) in detecting apical periodontitis (AP) using histopathological findings as a reference standard.

    METHODOLOGY: Jaw sections containing 67 teeth (86 roots) were collected from nine fresh, unclaimed bodies that were due for cremation. Imaging was carried out to detect AP lesions using film and digital PR with a centred view (FP and DP groups); film and digital PR combining central with 10˚ mesially and distally angled (parallax) views (FPS and DPS groups). All specimens underwent histopathological examination to confirm the diagnosis of AP. Sensitivity, specificity and predictive values of PR were analysed using rater mean (n = 5). Receiver operating characteristics (ROC) analysis was carried out.

    RESULTS: Sensitivity was 0.16, 0.37, 0.27 and 0.38 for FP, FPS, DP and DPS, respectively. Both FP and FPS had specificity and positive predictive values of 1.0, whilst DP and DPS had specificity and positive predictive values of 0.99. Negative predictive value was 0.36, 0.43, 0.39 and 0.44 for FP, FPS, DP and DPS, respectively. Area under the curve (AUC) for the various imaging methods was 0.562 (FP), 0.629 (DP), 0.685 (FPS), 0.6880 (DPS).

    CONCLUSIONS: The diagnostic accuracy of single digital periapical radiography was significantly better than single film periapical radiography. The inclusion of two additional horizontal (parallax) angulated periapical radiograph images (mesial and distal horizontal angulations) significantly improved detection of apical periodontitis.

    Matched MeSH terms: Sensitivity and Specificity
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