| 1. |
- Ngoc, Trinh Minh, et al.
(author)
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Ultralow power consumption gas sensor based on a self- heated nanojunction of SnO2 nanowires
- 2018
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In: RSC Advances. - : ROYAL SOC CHEMISTRY. - 2046-2069. ; 8:63, s. 36323-36330
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Journal article (peer-reviewed)abstract
- The long duration of a working device with a limited battery capacity requires gas sensors with low power consumption. A self-heated gas sensor is a highly promising candidate to satisfy this requirement. In this study, two gas sensors with sparse and dense SnO2 nanowire (NW) networks were investigated under the Joule heating effect at the nanojunction. Results showed that the local heating nanojunction was effective for NO2 sensing but generally not for reduction gases. At 1 W, the sparse NW sensor showed a good sensing performance to the NO2 gas. The dense SnO2 NW network required a high-power supply for gas-sensitive activation, but was suitable for reduction gases. A power of approximately 500 W was also needed for a fast recovery time. Notably, the dense NW sensor can response to ethanol and H2S gases. Results also showed that the self-heated sensors were simple in design and reproducible in terms of the fabrication process.
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| 2. |
- Tran, Thi-Thuy-Quynh, et al.
(author)
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Network Coding with Multimedia Transmission and Cognitive Networking: An Implementation based on Software-Defined Radio
- 2020
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In: REV Journal on Electronics and Communications. ; 10:3-4, s. 72-84
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Journal article (peer-reviewed)abstract
- Network coding (NC) is considered a breakthrough to improve throughput, robustness, and security of wireless networks. Although the theoretical aspects of NC have been extensively investigated, there have been only few experiments with pure NC schematics. This paper presents an implementation of NC under a two-way relay model and extends it to two non-straightforward scenarios: (i) multimedia transmission with layered coding and multiple-description coding, and (ii) cognitive radio with Vandermonde frequency division multiplexing (VFDM). The implementation is in real time and based on software-defined radio (SDR). The experimental results show that, by combining NC and source coding, we can control the quality of the received multimedia content in an on-demand manner. Whereas in the VFDM-based cognitive radio, the quality of the received content in the primary receiver is low (due to imperfect channel estimation) yet retrievable. Our implementation results serve as a proof for the practicability of network coding in relevant applications.
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| 3. |
- Cuc, Nguyen Thi Thu, et al.
(author)
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Hot water treatment prevents Aphelenchoides besseyi damage to Polianthes tuberosa crops in the Mekong Delta of Vietnam
- 2010
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In: Crop Protection. - 0261-2194. ; 29:6, s. 599-602
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Journal article (peer-reviewed)abstract
- Polianthes tuberosa is a commercially valuable flower crop in the Mekong Delta of Vietnam that is propagated by the harvesting and planting of bulbs. The cultivation of P. tuberosa is infected by an endemic Aphelenchoides besseyi nematode that damages a high proportion of plants and persists within the bulbs. Here we report on the comparison of hot water and pesticide treatments as control methods to protect P. tuberosa from A. besseyi damage, and conclude that a hot water treatment consisting of soaking bulbs in water for 30 minutes at 57 °C is the most efficacious method to produce healthy flowers in a cost-effective manner.
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| 4. |
- Da, Chau Thi, et al.
(author)
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Recycled pangasius pond sediments as organic fertilizer for vegetables cultivation : strategies for sustainable food production
- 2023
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In: Clean Technologies and Environmental Policy. - : Springer Science and Business Media LLC. - 1618-954X .- 1618-9558. ; 25:2, s. 369-380
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Journal article (peer-reviewed)abstract
- Intensive Pangasius aquaculture farming contributes to increased income and profits in Vietnam, but is also associated with many environmental problems, including pollution from nutrient-rich water and sediments that are released into the environment. This article investigates the feasibility of using Pangasius pond sediments (PPS) in combination with amendments of rice straw (RS) to fertilize cucumber (Cucumis sativus L.) and water spinach (Ipomoea aquatica Forssk) plant. The results showed that mixing a ratio of 30% PPS with 70% RS produced the highest nutrient concentrations. The study demonstrates that organic fertilizer produced from PPS in combination with chemical fertilizer can replace 2575% of the inorganic fertilizers used as a nutrient source for cucumber and water spinach, and also increase the vegetable production. The highest yields were found for treatment PPS-3 (a combination of 50% chemical fertilizer and 50% organic fertilizer used on cucumber), and for treatment PPSRS-4 (a combination of 25% chemical fertilizer and 75% organic fertilizer used on water spinach) in both the wet and dry season (P˂0.05). The lowest yields were found when growing cucumbers and water spinach either with 100% organic fertilizer (the treatment PPS-5) or with 100% chemical fertilizer (the control treatment PPS-1), respectively (P˂0.05). Overall, the results indicated that the recycling of PPS as organic fertilizer and chemical fertilizer in combination for vegetable cultivation is more environmentally friendly as compared to using only chemical fertilizers.
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| 5. |
- Ngoc, Trinh Minh, 1978-, et al.
(author)
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H2S Sensing Characteristics of Self-heated Ag-coated SnO2 nanowires
- 2017
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In: Proceeding of the 12th Asian Conference on Chemical Sensors (ACCS2017). - Hanoi. ; , s. 350-353
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Conference paper (other academic/artistic)abstract
- The H2S gas sensing characterization of gas sensors based on the SnO2 nanowires network has been reported by several research groups. However, the self-heated gas sensor using Ag-coated SnO2 nanowires network for sensing H2S was investigated the first times. In this study, we will report on the effected of density SnO2 nanowires network on H2S sensitivity. The SnO2 nanowires network density can be controlled bythe distance between sensor electrodes. After SnO2 nanowires decorated with Ag, the results showt hat the H2S gas sensing properties depend on the density of the SnO2 nanowires network. Asthe density of SnO2 nanowires network increases, the response of sensors decreases. Thesensor can operate at as low power as 2 mW to H2S gas concentration of 0.25 ppm. The responseand recovery times of sensor are about 200 s. Moreover, working at low operating power gives us the benefit of energy saving as well as the elongation of lifetime.
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| 6. |
- Nguyen, Thanh N, et al.
(author)
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Global Impact of the COVID-19 Pandemic on Stroke Volumes and Cerebrovascular Events: A 1-Year Follow-up.
- 2023
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In: Neurology. - 1526-632X. ; 100:4
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Journal article (peer-reviewed)abstract
- Declines in stroke admission, IV thrombolysis (IVT), and mechanical thrombectomy volumes were reported during the first wave of the COVID-19 pandemic. There is a paucity of data on the longer-term effect of the pandemic on stroke volumes over the course of a year and through the second wave of the pandemic. We sought to measure the effect of the COVID-19 pandemic on the volumes of stroke admissions, intracranial hemorrhage (ICH), IVT, and mechanical thrombectomy over a 1-year period at the onset of the pandemic (March 1, 2020, to February 28, 2021) compared with the immediately preceding year (March 1, 2019, to February 29, 2020).We conducted a longitudinal retrospective study across 6 continents, 56 countries, and 275 stroke centers. We collected volume data for COVID-19 admissions and 4 stroke metrics: ischemic stroke admissions, ICH admissions, IVT treatments, and mechanical thrombectomy procedures. Diagnoses were identified by their ICD-10 codes or classifications in stroke databases.There were 148,895 stroke admissions in the 1 year immediately before compared with 138,453 admissions during the 1-year pandemic, representing a 7% decline (95% CI [95% CI 7.1-6.9]; p < 0.0001). ICH volumes declined from 29,585 to 28,156 (4.8% [5.1-4.6]; p < 0.0001) and IVT volume from 24,584 to 23,077 (6.1% [6.4-5.8]; p < 0.0001). Larger declines were observed at high-volume compared with low-volume centers (all p < 0.0001). There was no significant change in mechanical thrombectomy volumes (0.7% [0.6-0.9]; p = 0.49). Stroke was diagnosed in 1.3% [1.31-1.38] of 406,792 COVID-19 hospitalizations. SARS-CoV-2 infection was present in 2.9% ([2.82-2.97], 5,656/195,539) of all stroke hospitalizations.There was a global decline and shift to lower-volume centers of stroke admission volumes, ICH volumes, and IVT volumes during the 1st year of the COVID-19 pandemic compared with the prior year. Mechanical thrombectomy volumes were preserved. These results suggest preservation in the stroke care of higher severity of disease through the first pandemic year.This study is registered under NCT04934020.
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| 7. |
- Pham, Binh Thai, et al.
(author)
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A Novel Hybrid Soft Computing Model Using Random Forest and Particle Swarm Optimization for Estimation of Undrained Shear Strength of Soil
- 2020
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In: Sustainability. - Switzerland : MDPI. - 2071-1050. ; 12:6
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Journal article (peer-reviewed)abstract
- Determination of shear strength of soil is very important in civilengineering for foundation design, earth and rock fill dam design, highway and airfield design,stability of slopes and cuts, and in the design of coastal structures. In this study, a novel hybrid softcomputing model (RF-PSO) of random forest (RF) and particle swarm optimization (PSO) wasdeveloped and used to estimate the undrained shear strength of soil based on the clay content (%),moisture content (%), specific gravity (%), void ratio (%), liquid limit (%), and plastic limit (%). Inthis study, the experimental results of 127 soil samples from national highway project Hai Phong-Thai Binh of Vietnam were used to generate datasets for training and validating models. Pearsoncorrelation coefficient (R) method was used to evaluate and compare performance of the proposedmodel with single RF model. The results show that the proposed hybrid model (RF-PSO) achieveda high accuracy performance (R = 0.89) in the prediction of shear strength of soil. Validation of themodels also indicated that RF-PSO model (R = 0.89 and Root Mean Square Error (RMSE) = 0.453) issuperior to the single RF model without optimization (R = 0.87 and RMSE = 0.48). Thus, theproposed hybrid model (RF-PSO) can be used for accurate estimation of shear strength which canbe used for the suitable designing of civil engineering structures.
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| 8. |
- Thanh, Dang Trung, et al.
(author)
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Effects of organic fertilizers produced from fish pond sediment on growth performances and yield of Malabar and Amaranthus vegetables
- 2023
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In: Frontiers in Sustainable Food Systems. - : Frontiers Media SA. - 2571-581X. ; 7
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Journal article (peer-reviewed)abstract
- The increasing intensification of aquaculture production requires the development of strategies to reduce its environmental impacts such as the pollution caused by the discharge of nutrient-rich sediments into local water bodies. This research was undertaken to investigate and evaluate the effect of using organic fertilizers produced from the pond sludge of freshwater snakehead fish (Channa striata) composted with organic amendments of peanut shells and coir fiber on growth performance indices and yields of Malabar spinach (Basella alba L.) and Amaranthus cruentus (Amaranthus L.) vegetables in the dry and wet seasons. An organic fertilizer quality experiment showed that the richest nutrient contents of the produced organic fertilizer were achieved when using 30% sludge mixed with 70% organic amendments (50% peanut shells + 50% coir fiber). This was selected and used for a vegetable cultivation experiment. For the reference treatment, only chemical fertilizer was applied, while in the other four treatments, 25, 50, 75, and 100% of the chemical fertilizer were substituted with the organic fertilizer. A 25–50% reduction in the chemical fertilizer application resulted in better growth performance indices and final yields than the other treatments, including the reference treatment, for both crops. The highest yields of Malabar spinach and Amaranthus cruentus vegetables were found in Treatment 3 (50% chemical fertilizer combined with 50% organic fertilizer), followed by Treatment 2 (25% organic fertilizer combined with 75% inorganic fertilizer) (P < 0.05). The results show that the reuse of sludge from snakehead fish ponds mixed with agricultural by-products as organic fertilizer for vegetables not only improves vegetable productivity but also reduces the costs of chemical fertilizer and decreases environmental pollution.
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| 9. |
- Ahmad, Amais, et al.
(author)
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IMI – Oral biopharmaceutics tools project – Evaluation of bottom-up PBPK prediction success part 4 : Prediction accuracy and software comparisons with improved data and modelling strategies
- 2020
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In: European journal of pharmaceutics and biopharmaceutics. - : Elsevier BV. - 0939-6411 .- 1873-3441. ; 156, s. 50-63
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Journal article (peer-reviewed)abstract
- Oral drug absorption is a complex process depending on many factors, including the physicochemical properties of the drug, formulation characteristics and their interplay with gastrointestinal physiology and biology. Physiological-based pharmacokinetic (PBPK) models integrate all available information on gastro-intestinal system with drug and formulation data to predict oral drug absorption. The latter together with in vitro-in vivo extrapolation and other preclinical data on drug disposition can be used to predict plasma concentration-time profiles in silico. Despite recent successes of PBPK in many areas of drug development, an improvement in their utility for evaluating oral absorption is much needed. Current status of predictive performance, within the confinement of commonly available in vitro data on drugs and formulations alongside systems information, were tested using 3 PBPK software packages (GI-Sim (ver.4.1), Simcyp® Simulator (ver.15.0.86.0), and GastroPlusTM (ver.9.0.00xx)). This was part of the Innovative Medicines Initiative (IMI) Oral Biopharmaceutics Tools (OrBiTo) project.Fifty eight active pharmaceutical ingredients (APIs) were qualified from the OrBiTo database to be part of the investigation based on a priori set criteria on availability of minimum necessary information to allow modelling exercise. The set entailed over 200 human clinical studies with over 700 study arms. These were simulated using input parameters which had been harmonised by a panel of experts across different software packages prior to conduct of any simulation. Overall prediction performance and software packages comparison were evaluated based on performance indicators (Fold error (FE), Average fold error (AFE) and absolute average fold error (AAFE)) of pharmacokinetic (PK) parameters.On average, PK parameters (Area Under the Concentration-time curve (AUC0-tlast), Maximal concentration (Cmax), half-life (t1/2)) were predicted with AFE values between 1.11 and 1.97. Variability in FEs of these PK parameters was relatively high with AAFE values ranging from 2.08 to 2.74. Around half of the simulations were within the 2-fold error for AUC0-tlast and around 90% of the simulations were within 10-fold error for AUC0-tlast. Oral bioavailability (Foral) predictions, which were limited to 19 APIs having intravenous (i.v.) human data, showed AFE and AAFE of values 1.37 and 1.75 respectively. Across different APIs, AFE of AUC0-tlast predictions were between 0.22 and 22.76 with 70% of the APIs showing an AFE > 1. When compared across different formulations and routes of administration, AUC0-tlast for oral controlled release and i.v. administration were better predicted than that for oral immediate release formulations. Average predictive performance did not clearly differ between software packages but some APIs showed a high level of variability in predictive performance across different software packages. This variability could be related to several factors such as compound specific properties, the quality and availability of information, and errors in scaling from in vitro and preclinical in vivo data to human in vivo behaviour which will be explored further. Results were compared with previous similar exercise when the input data selection was carried by the modeller rather than a panel of experts on each in vitro test. Overall, average predictive performance was increased as reflected in smaller AAFE value of 2.8 as compared to AAFE value of 3.8 in case of previous exercise.
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| 10. |
- Duong, Quang Trung, et al.
(author)
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Ergodic Capacity of Cooperative Networks Using Adaptive Transmission and Selection Combining
- 2009
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Conference paper (peer-reviewed)abstract
- Closed-form expressions for channel capacity of repetition-based cooperative networks under adaptive transmission with selection combining are presented under the assumption of independent Rayleigh fading. Specifically, three different adaptive techniques are investigated: optimal simultaneous power and rate adaptation (OPRA), constant power with optimal rate adaptation (OPA) and channel inversion with fixed rate (TIFR). Among them, for an arbitrary number of relays, TIFR gives the worst channel capacity; OPRA gives the best channel capacity and ORA has a channel capacity quality in between the others. The analysis results, based on the upper and lower bound of the end-to-end SNR, agree very well with the simulated results and definitely show the impact of selection combining on the calculated channel capacity per unit bandwidth
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