1. |
- Tran, Dien M., et al.
(author)
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High prevalence of colonisation with carbapenem-resistant Enterobacteriaceae among patients admitted to Vietnamese hospitals : Risk factors and burden of disease
- 2019
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In: Journal of Infection. - : Saunders Elsevier. - 0163-4453 .- 1532-2742. ; 79:2, s. 115-122
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Journal article (peer-reviewed)abstract
- BackgroundCarbapenem-resistant Enterobacteriaceae (CRE) is an increasing problem worldwide, but particularly problematic in low- and middle-income countries (LMIC) due to limitations of resources for surveillance of CRE and infection prevention and control (IPC).MethodsA point prevalence survey (PPS) with screening for colonisation with CRE was conducted on 2233 patients admitted to neonatal, paediatric and adult care at 12 Vietnamese hospitals located in northern, central and southern Vietnam during 2017 and 2018. CRE colonisation was determined by culturing of faecal specimens on selective agar for CRE. Risk factors for CRE colonisation were evaluated. A CRE admission and discharge screening sub-study was conducted among one of the most vulnerable patient groups; infants treated at an 80-bed Neonatal ICU from March throughout June 2017 to assess CRE acquisition, hospital-acquired infection (HAI) and treatment outcome.ResultsA total of 1165 (52%) patients were colonised with CRE, most commonly Klebsiella pneumoniae (n=805), Escherichia coli (n=682) and Enterobacter spp. (n=61). Duration of hospital stay, HAI and treatment with a carbapenem were independent risk factors for CRE colonisation. The PPS showed that the prevalence of CRE colonisation increased on average 4.2 % per day and mean CRE colonisation rates increased from 13% on the day of admission to 89% at day 15 of hospital stay. At the NICU CRE colonisation increased from 32% at admission to 87% at discharge, mortality was significantly associated (OR 5•5, P < 0•01) with CRE colonisation and HAI on admission.ConclusionThese data indicate that there is an epidemic spread of CRE in Vietnamese hospitals with rapid transmission to hospitalised patients.
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2. |
- Huong, Le Thi, et al.
(author)
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Diet and nutritional status among children 24-59 months by seasons in a mountainous area of Northern Vietnam in 2012
- 2014
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In: Global Health Action. - : Co-Action publishing. - 1654-9716 .- 1654-9880. ; 7
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Journal article (peer-reviewed)abstract
- BACKGROUND: Seasonal variation affects food availability. However, it is not clear if it affects dietary intake and nutritional status of children in Vietnam. OBJECTIVES: This paper aims at examining the seasonal variation in nutrition status and dietary intake of children aged 24-59 months. DESIGN: A repeated cross-sectional study design was used to collect data of changes in nutritional status and diets of children from 24 to 59 months through four seasons in Chiem Hoa district, Tuyen Quang province, a predominately rural mountainous province of northern Vietnam. The quantitative component includes anthropometric measurements, 24 hours dietary recall and socio-economic characteristics. The qualitative component was conducted through focus group discussions (FGDs) with mothers of the children surveyed in the quantitative component. The purpose of FGDs was to explore the food habits of children during the different seasons and the behaviours of their mothers in relation to the food that they provide during these seasons. RESULTS: The prevalence of underweight among children aged 24-59 months is estimated at around 20-25%; it peaked in summer (24.9%) and reached a low in winter (21.3%). The prevalence of stunting was highest in summer (29.8%) and lowest in winter (22.2%). The prevalence of wasting in children was higher in spring and autumn (14.3%) and lower in summer (9.3%). Energy intake of children was highest in the autumn (1259.3 kcal) and lowest in the summer (996.9 kcal). Most of the energy and the nutrient intakes during the four seasons did not meet the Vietnamese National Institute of Nutrition recommendation. CONCLUSIONS: Our study describes some seasonal variation in nutrition status and energy intake among children in a mountainous area northern Vietnam. Our study indicated that the prevalence of stunting and underweight was higher in summer and autumn, while the prevalence of wasting was higher in spring and autumn. Energy intake did not always meet national recommendations, especially in summer.
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3. |
- Hollestelle, Antoinette, et al.
(author)
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No clinical utility of KRAS variant rs61764370 for ovarian or breast cancer
- 2016
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In: Gynecologic Oncology. - : Elsevier BV. - 0090-8258 .- 1095-6859. ; 141:2, s. 386-401
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Journal article (peer-reviewed)abstract
- Objective Clinical genetic testing is commercially available for rs61764370, an inherited variant residing in a KRAS 3′ UTR microRNA binding site, based on suggested associations with increased ovarian and breast cancer risk as well as with survival time. However, prior studies, emphasizing particular subgroups, were relatively small. Therefore, we comprehensively evaluated ovarian and breast cancer risks as well as clinical outcome associated with rs61764370. Methods Centralized genotyping and analysis were performed for 140,012 women enrolled in the Ovarian Cancer Association Consortium (15,357 ovarian cancer patients; 30,816 controls), the Breast Cancer Association Consortium (33,530 breast cancer patients; 37,640 controls), and the Consortium of Modifiers of BRCA1 and BRCA2 (14,765 BRCA1 and 7904 BRCA2 mutation carriers). Results We found no association with risk of ovarian cancer (OR = 0.99, 95% CI 0.94-1.04, p = 0.74) or breast cancer (OR = 0.98, 95% CI 0.94-1.01, p = 0.19) and results were consistent among mutation carriers (BRCA1, ovarian cancer HR = 1.09, 95% CI 0.97-1.23, p = 0.14, breast cancer HR = 1.04, 95% CI 0.97-1.12, p = 0.27; BRCA2, ovarian cancer HR = 0.89, 95% CI 0.71-1.13, p = 0.34, breast cancer HR = 1.06, 95% CI 0.94-1.19, p = 0.35). Null results were also obtained for associations with overall survival following ovarian cancer (HR = 0.94, 95% CI 0.83-1.07, p = 0.38), breast cancer (HR = 0.96, 95% CI 0.87-1.06, p = 0.38), and all other previously-reported associations. Conclusions rs61764370 is not associated with risk of ovarian or breast cancer nor with clinical outcome for patients with these cancers. Therefore, genotyping this variant has no clinical utility related to the prediction or management of these cancers.
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4. |
- Phu, Vu Dinh, et al.
(author)
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Burden of Hospital Acquired Infections and Antimicrobial Use in Vietnamese Adult Intensive Care Units
- 2016
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In: PLOS ONE. - : PUBLIC LIBRARY SCIENCE. - 1932-6203. ; 11:1
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Journal article (peer-reviewed)abstract
- Background Vietnam is a lower middle-income country with no national surveillance system for hospital-acquired infections (HAIs). We assessed the prevalence of hospital-acquired infections and antimicrobial use in adult intensive care units (ICUs) across Vietnam. Methods Monthly repeated point prevalence surveys were systematically conducted to assess HAI prevalence and antimicrobial use in 15 adult ICUs across Vietnam. Adults admitted to participating ICUs before 08: 00 a.m. on the survey day were included. Results Among 3287 patients enrolled, the HAI prevalence was 29.5% (965/3266 patients, 21 missing). Pneumonia accounted for 79.4% (804/1012) of HAIs Most HAIs (84.5% [855/1012]) were acquired in the survey hospital with 42.5% (363/855) acquired prior to ICU admission and 57.5% (492/855) developed during ICU admission. In multivariate analysis, the strongest risk factors for HAI acquired in ICU were: intubation (OR 2.76), urinary catheter (OR 2.12), no involvement of a family member in patient care (OR 1.94), and surgery after admission (OR 1.66). 726 bacterial isolates were cultured from 622/1012 HAIs, most frequently Acinetobacter baumannii (177/726 [24.4%]), Pseudomonas aeruginosa (100/726 [13.8%]), and Klebsiella pneumoniae (84/726 [11.6%]), with carbapenem resistance rates of 89.2%, 55.7%, and 14.9% respectively. Antimicrobials were prescribed for 84.8% (2787/ 3287) patients, with 73.7% of patients receiving two or more. The most common antimicrobial groups were third generation cephalosporins, fluoroquinolones, and carbapenems (20.1%, 19.4%, and 14.1% of total antimicrobials, respectively). Conclusion A high prevalence of HAIs was observed, mainly caused by Gram-negative bacteria with high carbapenem resistance rates. This in combination with a high rate of antimicrobial use illustrates the urgent need to improve rational antimicrobial use and infection control efforts.
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5. |
- Son, Hoang Nghia, et al.
(author)
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Effects of simulated microgravity on the morphology of mouse embryonic fibroblasts (MEFs)
- 2020
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In: Romanian Biotechnological Letters. - Bucharest : University of Bucharest. - 1224-5984 .- 2248-3942. ; 25:6, s. 2156-2160
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Journal article (peer-reviewed)abstract
- This study aimed to assess the effects of simulated microgravity on mouse embryonic fibroblast (MEF) morphology. The results showed that the area of MEFs under simulated microgravity was 7843.39 +/- 551.31 mu m(2) which was lower than the control group (9832.72 +/- 453.86 mu m(2)) (p < 0.001). The nuclear area of MEFs under simulated microgravity (290.76 +/- 4.58 mu m(2)) and the control group (296.8 +/- 4.58 mu m(2)) did not statistically differ. In addition, the nuclear shape value of the MEFs under simulated microgravity and the control group did not statistically differ (0.86 +/- 0.006 vs. 0.87 +/- 0.003, respectively). The nuclear intensity of MEFs under simulated microgravity (19361 +/- 852) was higher than the control group (16997 +/- 285) (P <0.05). Moreover, the flow cytometry analysis indicated the reduced GO/G1 phase cell ratio and the increased S phase and G2/M phase cell ratio in MEFs under simulated microgravity. Simulated microgravity also induced a decrease in diameter of actin filament bundles of the MEFs under simulated microgravity (1.61 +/- 0.33 mu m) compared to the control group (1.79 +/- 0.32 mu m) (P <0.01). These results revealed that simulated microgravity is capable of inducing the morphological changes of mouse embryonic fibroblasts.
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6. |
- Thu Thao, Bui T., et al.
(author)
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Enhancement of selective monoaromatic hydrocarbon and syngas products from fast pyrolysis of cassava stalks over Co, Mo promoted Ni catalysts
- 2024
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In: Journal of the Energy Institute. - 1743-9671 .- 1746-0220. ; 115
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Journal article (peer-reviewed)abstract
- Catalytic fast pyrolysis of cassava stalks has been intriguing as a promising, feasible chemical refinery method in terms of waste-to-energy conversion from cassava cultivation. This study aims to determine the synergetic influence of Mo and Co on Ni catalysts (Ni, Ni–Mo, and Ni–Co) prepared via ultrasonic-assisted incipient wetness impregnation method for catalytic pyrolysis vapor upgrading. The results indicated that Co and Mo enhance the reducibility of NiO and promote weak-to-medium acidity, thereby enhancing Ni's performance. Mono-Ni favors cracking deoxygenation, whereas oxophilicity promoters particularly enhance the oxygen absorbability efficiency to selective deoxygenated production. A fine Ni dispersion on CoNi/SiO2 catalyst was observed to positively affect the production of monoaromatic hydrocarbons (46.10 %), in contrast to those without promoters (21.63 %). This is attributed to an optimal Ni-metallic distribution with a small crystal size of 7.01 nm and a high surface area of 342.6 m2 g−1, highlighting the effectiveness of the promoter-assisted Ni catalyst. Additionally, a high yield of H2 (66.9 %) in non-condensable gas was recorded at 550 °C. The study suggests that a simplified approach to developing Ni-based catalysts could enhance the eco-friendliness of commercial catalysts, thereby facilitating the scale-up of biomass pyrolysis applications.
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7. |
- Bich, Tran Huu, et al.
(author)
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Father's involvement and its effect on early breastfeeding practices in Viet Nam.
- 2016
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In: Maternal and Child Nutrition. - : Wiley. - 1740-8695 .- 1740-8709. ; 12:4, s. 768-777
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Journal article (peer-reviewed)abstract
- Fathers have an important but often neglected role in the promotion of healthy breastfeeding practices in developing countries. A community-based education intervention was designed to mobilize fathers' support for early breastfeeding. This study aimed to evaluate an education intervention targeting fathers to increase the proportion of early breastfeeding initiation and to reduce prelacteal feeding. Quasi-experimental study design was used to compare intervention and control areas located in two non-adjacent rural districts that shared similar demographic and health service characteristics in northern Viet Nam. Fathers and expectant fathers with pregnant wives from 7 to 30 weeks gestational age were recruited. Fathers in the intervention area received breastfeeding education materials, counselling services at a commune health centre and household visits. They were also invited to participate in a breastfeeding promotion social event. After intervention, early breastfeeding initiation rate was 81.2% in the intervention area and 39.6% in the control area (P < 0.001). Babies in the intervention area were more likely to be breastfed within the first hour after birth [odds ratio (OR) 7.64, 95% confidence interval (CI) 4.81-12.12] and not to receive any prelacteal feeding (OR 4.43, 95% CI 2.88-6.82) compared with those in the control area. Fathers may positively influence the breastfeeding practices of mothers, and as a resource for early childcare, they can be mobilized in programmes aimed at improving the early initiation of breastfeeding.
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8. |
- Cao, Le Phuong, 1983-
(author)
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Optimal Transmit Strategies for Multi-antenna Systems with Joint Sum and Per-antenna Power Constraints
- 2019
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Doctoral thesis (other academic/artistic)abstract
- Nowadays, wireless communications have become an essential part of our daily life. During the last decade, both the number of users and their demands for wireless data have tremendously increased. Multi-antenna communication is a promising solution to meet this ever-growing traffic demands. In this dissertation, we study the optimal transmit strategies for multi-antenna systems with advanced power constraints, in particular joint sum and per-antenna power constraints. We focus on three different models including multi-antenna point-to-point channels, wiretap channels and massive multiple-input multiple-output (MIMO) setups. The solutions are provided either in closed-form or efficient iterative algorithms, which are ready to be implemented in practical systems.The first part is concerned with the optimal transmit strategies for point-to-point multiple-input single-output (MISO) and multiple-input multiple-output (MIMO) channels with joint sum and per-antenna power constraints. For the Gaussian MISO channels, a closed-form characterization of an optimal beamforming strategy is derived. It is shown that we can always find an optimal beamforming transmit strategy that allocates the maximal sum power with phases matched to the complex channel coefficients. An interesting property of the optimal power allocation is that whenever the optimal power allocation of the corresponding problem with sum power constraint only exceeds per-antenna power constraints, it is optimal to allocate maximal per-antenna power to those antennas to satisfy the per-antenna power constraints. The remaining power is distributed among the other antennas whose optimal allocation follows from a reduced joint sum and per-antenna power constraints problem with fewer channel coefficients and a reduced sum power constraint. For the Gaussian MIMO channels, it is shown that if an unconstraint optimal power allocation for an antenna exceeds a per-antenna power constraint, then the maximal power for this antenna is used in the constraint optimal transmit strategy. This observation is then used in an iterative algorithm to compute the optimal transmit strategy in closed-form.In the second part of the thesis, we investigate the optimal transmit strategies for Gaussian MISO wiretap channels. Motivated by the fact that the non-secure capacity of the MISO wiretap channels is usually larger than the secrecy capacity, we study the optimal trade-off between those two rates with different power constraint settings, in particular, sum power constraint only, per-antenna power constraints only, and joint sum and per-antenna power constraints. To characterize the boundary of the optimal rate region, which describes the optimal trade-off between non-secure transmission and secrecy rates, related problems to find optimal transmit strategies that maximize the weighted rate sum with different power constraints are derived. Since these problems are not necessarily convex, equivalent problem formulation is used to derive optimal transmit strategies. A closed-formsolution is provided for sum power constraint only problem. Under per-antenna power constraints, necessary conditions to find the optimal power allocation are provided. Sufficient conditions, however, are available for the case of two transmit antennas only. For the special case of parallel channels, the optimal transmit strategies can deduced from an equivalent point-to-point channel problem. In this case, there is no trade-off between secrecy and non-secrecy rate, i.e., there is onlya transmit strategy that maximizes both rates.Finally, the optimal transmit strategies for large-scale MISO and massive MIMO systems with sub-connected hybrid analog-digital beamforming architecture, RF chain and per-antenna power constraints are studied. The system is configured such that each RF chain serves a group of antennas. For the large-scale MISO system, necessary and sufficient conditions to design the optimal digital and analog precoders are provided. It is optimal that the phase at each antenna is matched tothe channel so that we have constructive alignment. Unfortunately, for the massive MIMO system, only necessary conditions are provided. The necessary conditions to design the digital precoder are established based on a generalized water-filling and joint sum and per-antenna optimal power allocation solution, while the analog precoder is based on a per-antenna power allocation solution only. Further, we provide the optimal power allocation for sub-connected setups based on two properties: (i) Each RF chain uses full power and (ii) if the optimal power allocation of the unconstraint problem violates a per-antenna power constraint then it is optimal to allocate the maximal power for that antenna. The results in the dissertation demonstrate that future wireless networks can achieved higher data rates with less power consumption. The designs of optimal transmit strategies provided in this dissertation are valuable for ongoing implementations in future wireless networks. The insights offered through the analysis and design of the optimal transmit strategies in the dissertation also provide the understanding of the optimal power allocation on practical multi-antenna systems.
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9. |
- Cao, Le Phuong, et al.
(author)
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Optimal transmit strategy for MIMO channels with joint sum and per-antenna power constraints
- 2017
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In: 2017 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP). - : IEEE. - 9781509041176 ; , s. 3569-3573
-
Conference paper (peer-reviewed)abstract
- This paper studies optimal transmit strategies for multiple-input multiple-output (MIMO) Gaussian channels with joint sum and per-antenna power constraints. It is shown that if an unconstraint optimal allocation for an antenna exceeds a per-antenna power constraint, then the maximal power for this antenna is used in the constraint optimal transmit strategy. This observation is then used in an iterative algorithm to compute the optimal transmit strategy in closed-form. Finally, a numerical example is provided to illustrate the theoretical results.
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10. |
- Cao, Le Phuong, et al.
(author)
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Transmit Beamforming for Single-User Large-Scale MISO Systems With Sub-Connected Architecture and Power Constraints
- 2018
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In: IEEE Communications Letters. - : IEEE. - 1089-7798 .- 1558-2558. ; 22:10, s. 2096-2099
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Journal article (peer-reviewed)abstract
- This letter considers optimal transmit beamforming for a sub-connected large-scale MISO system with RF chain and per-antenna power constraints. The system is configured such that each RF chain serves a group of antennas. For the hybrid scheme, necessary and sufficient conditions to design the optimal digital and analog precoders are provided. It is shown that, in the optimum, the optimal phase shift at each antenna has to match the channel coefficient and the phase of the digital precoder. In addition, an iterative algorithm is provided to find the optimal power allocation. We study the case where the power constraint on each RF chain is smaller than the sum of the corresponding per-antenna power constraints. Then, the optimal power is allocated based on two properties: each RF chain uses full power and if the optimal power allocation of the unconstraint problem violates a per-antenna power constraint then it is optimal to allocate the maximal power for that antenna.
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