15 results on '"DUNG, N. V."'
Search Results
2. GALAD score and a proposal for GALADUS model for detecting hepatocellular carcinoma in Vietnamese patients with chronic liver disease.
- Author
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PHUONG, P.-C., KHOA, M.-T., LOI, N.-T., QUYNH, V. T. T., LUAN, N.-D., MAI, N. T. H., DUNG, N.-V., HUNG, N.-Q., LIEU, D.-Q., NAM, L.-V., TRA, D.-T., THAI, P.-V., and DUC, N.-M.
- Abstract
OBJECTIVE: The GALAD score, a serum biomarker-based model, predicts the likelihood of hepatocellular carcinoma (HCC) in patients with chronic liver disease. We evaluated the performance of the GALAD score compared to that of liver ultrasound in detecting HCC. PATIENTS AND METHODS: This study recruited a group of 136 patients with HCC and a control group of 436 patients with cirrhosis or chronic hepatitis B or hepatitis C. The performance of the GALAD score and ultrasound in detecting HCC in these patients was analyzed using the area under the receiver operating characteristic curve (AUC). The sensitivity and specificity of the optimal GALAD score were compared to those of ultrasound. RESULTS: The AUC of the GALAD score for detecting HCC was 0.940 [95% confidence interval (CI) 0.92-0.96], higher than that of ultrasound [0.939 (0.91-0.96), p < 0.001]. At a threshold of 1.24, the GALAD score had a sensitivity of 91.2% and a specificity of 81.9% for detecting HCC. The AUC of the GALAD score for early HCC detection was 0.75 (95% CI 0.71-0.80, p < 0.001; threshold 1.13, sensitivity 87.5%, specificity 67.8%, p < 0.001). The combination of GALAD and ultrasound (GALADUS score) showed further improvement, achieving an AUC of 0.97 (95% CI 0.96-0.99; cut-off point 1.37, sensitivity 95.6%, specificity 89.2%, p < 0.001). CONCLUSIONS: In our study, the GALADUS score showed improved performance compared to the GALAD score. Therefore, we suggest that the performance of the GALAD score should be reconsidered and that it should be evaluated in combination with ultrasound for HCC detection. [ABSTRACT FROM AUTHOR]
- Published
- 2024
3. Continuous, large-scale simulation model for flood risk assessments: proof-of-concept
- Author
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Falter, D., Dung, N. V., Vorogushyn, S., Schröter, K., Hundecha, Y., Kreibich, H., Apel, H., Theisselmann, F., and Merz, B.
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- 2016
- Full Text
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4. The effect of antioxidants on the physical and chemical properties of rice oil, corn oil, peanut oil and Kraft paper.
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Dung, N. V. and Huong, H. L.
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RICE oil , *PEANUT oil , *KRAFT paper , *CORN oil , *CHEMICAL properties , *VEGETABLE oils - Abstract
This paper presents an experimental study on the physicochemical properties of rice oil, peanut oil, corn oil and Kraft paper immersed in these oils in the presence of antioxidants (butylated hydroxytoluene, tertiary butyl hydroquinone and Naugalube¯ 750). The experiments are performed on new and aged conditions. Ageing of oils is carried at 115 °C for 96 hours while Kraft paper is aged in oils at 130 °C for 164 hours. Both closed and open cup methods are used for ageing. The results show that ageing insignificantly affects the breakdown voltage, but markedly increases the acid number and the viscosity of the vegetable oils. The combination of tertiary butyl hydroquinone and either butylated hydroxytoluene or Naugalube¯ 750 slightly increases the breakdown voltage, but significantly raises the oxidation stability of the vegetable oils. This results in a reduction in the viscosity and the acid number of the vegetable oils. Moisture significantly affects the breakdown voltage of both vegetable and mineral oil. High moisture content results in low breakdown voltage. The results also show that ageing insignificantly affects the breakdown voltage, but markedly decreases the tensile strength of oil-impregnated paper. Although the presence of antioxidants does not increase the breakdown voltage of aged paper, these additives slow down the ageing process. This results in an increase in tensile strength of the paper. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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5. Opportunities for Chemical Engineers in the Australian Food Industries
- Author
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Bowrey, R G, Dung, N V, Fowler, R T, Putranon, R, and National Conference on Chemical Engineering 1979; Expanding Horizons in Chemical Engineering; Preprints of Papers
- Published
- 1979
6. THE METRIC APPROACH TO FIXED POINT THEOREMS IN METRIC-LIKE SPACES.
- Author
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DUNG, N. V., HIEU, N. T., and HANG, V. T. L.
- Subjects
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METRIC spaces , *GENERALIZED spaces , *SET theory , *MATHEMATICAL continuum , *QUASI-metric spaces - Abstract
By constructing two metrics from a given metric-like space we show that some fixed point theorems in metric-like spaces may be obtained from the corresponding results in metric spaces. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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7. Remarks on Metric-Type Spaces and Applications.
- Author
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Dung, N. V., Hang, V. T. L., and Sedghi, S.
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FIXED point theory , *METRIC spaces , *MATHEMATICS theorems , *CAUCHY sequences , *MATHEMATICAL proofs - Abstract
In this paper, we prove some properties of metric-type spaces. As applications, we show that fixed point theorems on bounded 2-metric spaces and S-metric spaces in [18, 22] and others may be obtained from certain fixed point theorems on metric-type spaces. [ABSTRACT FROM AUTHOR]
- Published
- 2015
8. Combined fluvial and pluvial urban flood hazard analysis: method development and application to Can Tho City, Mekong Delta, Vietnam.
- Author
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Apel, H., Trepat, O. M., Hung, N. N., Chinh, D. T., Merz, B., and Dung, N. V.
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FLOOD damage prevention ,FLUVIAL geomorphology ,PLUVIAL periods ,HYDRODYNAMICS ,ATMOSPHERIC models - Abstract
Many urban areas experience both fluvial and pluvial floods, because locations next to rivers are preferred settlement areas, and the predominantly sealed urban surface prevents infiltration and facilitates surface inundation. The latter problem is enhanced in cities with insufficient or non-existent sewer systems. While there are a number of approaches to analyse either fluvial or pluvial flood hazard, studies of combined fluvial and pluvial flood hazard are hardly available. Thus this study aims at the analysis of fluvial and pluvial flood hazard individually, but also at developing a method for the analysis of combined pluvial and fluvial flood hazard. This combined fluvial-pluvial flood hazard analysis is performed taking Can Tho city, the largest city in the Vietnamese part of the Mekong Delta, as example. In this tropical environment the annual monsoon triggered floods of the Mekong River can coincide with heavy local convective precipitation events causing both fluvial and pluvial flooding at the same time. Fluvial flood hazard was estimated with a copula based bivariate extreme value statistic for the gauge Kratie at the upper boundary of the Mekong Delta and a large-scale hydrodynamic model of the Mekong Delta. This provided the boundaries for 2-dimensional hydrodynamic inundation simulation for Can Tho city. Pluvial hazard was estimated by a peak-over-threshold frequency estimation based on local rain gauge data, and a stochastic rain storm generator. Inundation was simulated by a 2-dimensional hydrodynamic model implemented on a Graphical Processor Unit (GPU) for time-efficient flood propagation modelling. All hazards - fluvial, pluvial and combined - were accompanied by an uncertainty estimation considering the natural variability of the flood events. This resulted in probabilistic flood hazard maps showing the maximum inundation depths for a selected set of probabilities of occurrence, with maps showing the expectation (median) and the uncertainty by percentile maps. The results are critically discussed and ways for their usage in flood risk management are outlined. [ABSTRACT FROM AUTHOR]
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- 2015
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9. A study on positive streamer channels in Marcol Oil.
- Author
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Dung, N. V., Hoidalen, H. K., Linhjell, D., Lundgaard, L. E., and Unge, M.
- Abstract
The streamer channels in Marcol oil have been studied under the positive “step” voltages. Experiments were performed with a point-plane gap of 8 cm. Three kinds of streamer channels were observed around breakdown voltage. These are dark, partly illuminating, and fully illuminating (reillumination) channels. No current could be detected for the dark channels. The partly illuminating channels correlate with small current pulses in some hundreds of milli-amperes. However, the reilluminations are associated with much higher current pulses of some amperes. All kinds of channels occur simultaneously and propagate almost equally fast. Streamers with reilluminations almost always terminate with breakdown. On the other hand, streamers with dark or partly illuminating channels have much lower probability for breakdown. Reilluminations do not have significant effects on the propagation of non-breakdown and breakdown streamers as well as the time to cross the gap and breakdown. In the 2nd mode streamers, 30–50% of their branches are able to become illuminated, and the number of reilluminations as well as illuminating branches is proportional to the applied voltage. The effects of vacuum on streamers were also investigated. With vacuum, streamers travel with much lower voltage drop along the streamer channel. Therefore stopping length greatly increases, and the breakdown voltage drastically drops. All crossing streamers result in breakdown. The number of reilluminations in vacuum is lower than that in ambient pressure. The physics of the above streamer channels is discussed. [ABSTRACT FROM PUBLISHER]
- Published
- 2012
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10. REMARKS ON QUASI-METRIC SPACES.
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DUNG, N. V.
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METRIC geometry , *TOPOLOGY , *GENERALIZED spaces , *SET theory , *METRIC spaces - Abstract
In this paper, we prove some properties of quasi-metric spaces and state some fixed point theorems in this setting. As applications, we show that most of recent results on G-metric spaces in [3, 10] may be also implied from certain fixed point theorems on metric spaces and quasi-metric spaces. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
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11. Large-scale quantification of suspended sediment transport and deposition in the Mekong Delta.
- Author
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Manh, N. V., Dung, N. V., Hung, N. N., Merz, B., and Apel, H.
- Abstract
Sediment dynamics play a major role for the agricultural and fishery productivity of the Mekong Delta. However, the understanding of sediment dynamics in the Mekong Delta, one of the most complex river deltas in the world, is very limited. This is a consequence of its large extent, the intricate system of rivers, channels and floodplains and the scarcity of observations. This study quantifies, for the first time, the suspended sediment transport and sediment-nutrient deposition in the whole Mekong Delta. To this end, a quasi-2-D hydrodynamic model is combined with a cohesive sediment transport model. The combined model is calibrated automatically using six objective functions to represent the different aspects of the hydraulic and sediment transport components. The model is calibrated for the extreme flood season in 2011 and shows good performance for the two validation years with very different flood characteristics. It is shown how sediment transport and sediment deposition vary from Kratie at the entrance of the Delta to the coast. The main factors influencing the spatial sediment dynamics are the setup of rivers, channels and dike-rings, the sluice gate operations, the magnitude of the floods and tidal influences. The superposition of these factors leads to high spatial variability of sediment transport, in particular in the Vietnamese floodplains. Depending on the flood magnitude, the annual sedimentation rate averaged over the Vietnamese floodplains varies from 0.3 to 2.1 kgm
-2 yr-1 , and the ring dike floodplains trap between 1 and 6% of the total sediment load at Kratie. This is equivalent to 29 x 10³-440 x 10³ t of nutrients (N, P, K, TOC) deposited in the Vietnamese floodplains. This large-scale quantification provides a basis for estimating the benefits of the annual Mekong floods for agriculture and fishery, and is important information for assessing the effects of deltaic subsidence and climate change related sea level rise. [ABSTRACT FROM AUTHOR]- Published
- 2014
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12. Effects of reduced pressure and additives on streamers in white oil in long point-plane gap.
- Author
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Dung, N. V., Høidalen, H. K., Linhjell, D., Lundgaard, L. E., and Unge, M.
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ELECTRIC discharge research , *MINERAL oils , *BREAKDOWN voltage , *VELOCITY , *POLARITY (Physics) , *VOLTAGE reversal - Abstract
Recent experiments show that modern dielectric liquids behave differently from traditional mineral oil, particularly with respect to breakdown voltages for lightning impulse. This paper describes an experimental investigation addressing underlying reasons for this. The influences of reduced pressure and additives on streamers in white oil were investigated under both positive and negative polarities using an 8 cm long point-plane gap. Reduced pressure significantly accelerates streamers, thus increasing stopping length and reducing both breakdown and acceleration voltages. With increasing applied voltage, different typical propagation modes of streamers were recorded for both polarities. A low ionization potential additive strongly affects positive streamers. It significantly changes streamer velocity and reduces the breakdown voltage but increases the acceleration voltage where breakdown streamer velocity increases drastically. Adding an electron scavenger influences streamers of both polarities, but it mainly increases the velocity of negative streamers and results in a reduction of both the breakdown and the acceleration voltages. The propagation mechanisms of streamers are also discussed. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
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13. Multi-objective automatic calibration of hydrodynamic models utilizing inundation maps and gauge data.
- Author
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Dung, N. V., Merz, B., Bárdossy, A., Thang, T. D., and Apel, H.
- Subjects
MATHEMATICAL models of hydrodynamics ,FLOODS ,MAPS ,CALIBRATION ,HYDROLOGY ,STREAM-gauging stations ,REMOTE sensing ,SYNTHETIC aperture radar - Abstract
Automatic and multi-objective calibration of hydrodynamic models is - compared to other disciplines like e.g. hydrology - still underdeveloped. This has mainly two reasons: the lack of appropriate data and the large computational demand in terms of CPU-time. Both aspects are aggravated in large-scale applications. However, there are recent developments that improve the situation on both the data and computing side. Remote sensing, especially radar-based techniques proved to provide highly valuable information on flood extents, and in case high precision DEMs are present, also on spatially distributed inundation depths. On the computing side the use of parallelization techniques brought significant performance gains. In the presented study we build on these developments by calibrating a large-scale 1-dimensional hydrodynamic model of the whole Mekong Delta downstream of Kratie in Cambodia: we combined in-situ data from a network of river gauging stations, i.e. data with high temporal but low spatial resolution, with a series of inundation maps derived from ENVISAT Advanced Synthetic Aperture Radar (ASAR) satellite images, i.e. data with low temporal but high spatial resolution, in an multi- objective automatic calibration process. It is shown that an automatic, multi-objective calibration of hydrodynamic models, even of such complexity and on a large scale and complex as a model for the Mekong Delta, is possible. Furthermore, the calibration process revealed model deficiencies in the model structure, i.e. the representation of the dike system in Vietnam, which would have been difficult to detect by a standard manual calibration procedure. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
14. Multi-objective automatic calibration of hydrodynamic models utilizing inundation maps and gauge data.
- Author
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Dung, N. V., Merz, B., Bárdossy, A., Thang, T. D., and Apel, H.
- Abstract
Calibration of hydrodynamic models is -- compared to other disciplines like e.g. hydrology -- still underdeveloped. This has mainly two reasons: the lack of appropriate data and the large computational demand in terms of CPU-time. Both aspects are aggravated in large-scale applications. However, there are recent developments that improve the situation on both the data and computing side. Remote sensing, especially radar-based techniques proved to provide highly valuable information on food extents, and in case high precision DEMs are present, also on spatially distributed inundation depths. On the computing side the use of parallelization techniques brought significant performance gains. In the presented study we build on these developments by calibrating a large-scale 1-D hydrodynamic model of the whole Mekong Delta downstream of Kratie in Cambodia: we combined in-situ data from a network of river gauging stations, i.e. data with high temporal but low spatial resolution, with a series of inundation maps derived from ENVISAT Advanced Synthetic Aperture Radar (ASAR) satellite images, i.e. data with low temporal but high spatial resolution, in an multi-objective automatic calibration process. It is shown that an automatic, multi-objective calibration of hydrodynamic models, even of such complexity and on a large scale and complex as a model for the Mekong Delta, is possible. Furthermore, the calibration process revealed model de?ciencies in the model structure, i.e. the representation of the dike system in Vietnam, which would have been di?cult to detect by a standard manual calibration procedure. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
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15. First report of Lecanicillium fungicola var. aleophilum infecting white-button mushroom in Vietnam.
- Author
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Thao, L. D., Binh, V. T. P., Khanh, T. N., Thanh, H. M., Hien, L. T., Anh, P. T., Trang, T. T. T., Dung, N. V., and Hoai, H. T.
- Subjects
MUSHROOMS ,CULTIVATED mushroom ,PATHOGENIC microorganisms ,AGRICULTURAL productivity ,PLANT diseases - Abstract
The article focuses on report of Lecanicillium fungicola var. aleophilum infecting white-button mushroom in Vietnam. It mentions symptoms of sunken brown spots were observed three days post-inoculation and the same pathogen was re-isolated from symptomatic tissues. It also mentions Brown spots were the most serious disease observed in mushroom-growing areas, affected crops having a disease incidence leading to a significant decrease in productivity and quality.
- Published
- 2020
- Full Text
- View/download PDF
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