Antibiotic-Resistant Gram-negative Bacteria Carriage in Healthcare Workers Working in an Intensive Care Unit

Duong Bich Thuy,Duong Minh Cuong,Campbell James,Nguyen Van Minh Hoang,Nguyen Huu Hien,Bui Thi Bich Hanh,Nguyen Van Vinh Chau,McLaws Mary-Louise 대한감염학회 2021 Infection and Chemotherapy Vol.53 No.3

Little is known about antibiotic-resistant Gram-negative bacteria (GNB) intestinal carriage among healthcare workers (HCWs) in Vietnam. All HCWs at a tertiary intensive care units were asked to undertake weekly rectal swabs. Among 40 participants, 65% (26/40) carried extended spectrum β-lactamases (ESBL)/AmpC β-lactamase-producing Escherichia coli. Two HCWs colonized with ESBL/AmpC β-lactamase-producing Klebsiella pneumoniae. One HCW colonized with Acinetobacter baumannii. No one carried Pseudomonas spp.. A quarter (10/40) of HCWs were identified as persistent and frequent carriers. There is an urgent need to screen antibiotic-resistant GNB among HCWs and improve HCWs’ hand hygiene compliance to reduce the transmission of antibiotic-resistant GNB in the hospital.

Spectral and Energy Efficiencies in Full-Duplex Wireless Information and Power Transfer

Nguyen, Van-Dinh,Duong, Trung Q.,Tuan, Hoang Duong,Shin, Oh-Soon,Poor, H. Vincent Institute of Electrical and Electronics Engineers 2017 IEEE Transactions on Communications Vol. No.

<P>A communication system is considered consisting of a full-duplex multiple-antenna base station (BS) and multiple single-antenna downlink users (DLUs) and single-antenna uplink users (ULUs), where the latter need to harvest energy for transmitting information to the BS. The communication is thus divided into two phases. In the first phase, the BS uses all available antennas for conveying information to DLUs and wireless energy to ULUs via information and energy beamforming, respectively. In the second phase, ULUs send their independent information to the BS using their harvested energy while the BS transmits the information to the DLUs. In both the phases, the communication is operated at the same time and over the same frequency band. The aim is to maximize the sum rate and energy efficiency under ULU achievable information throughput constraints by jointly optimizing beamforming and time allocation. The utility functions of interest are nonconcave and the involved constraints are nonconvex, so these problems are computationally troublesome. To address them, path-following algorithms are proposed to arrive at least at local optima. The proposed algorithms iteratively improve the objectives with convergence guaranteed. Simulation results demonstrate that they achieve rapid convergence and outperform conventional solutions.</P>

An online Indigenous Knowledge Database on Climate Change Adaptation of Farmers in the Vietnam Mekong Delta

Van Hoa Nguyen,Thi Mai Phung Bui,Thanh Phong Le,Hoang Tung Nguyen,Minh Tuyen Truong,Minh Nhut Do,Van Nha Duong 인간식물환경학회 2022 인간식물환경학회지 Vol.25 No.6

Background and objective: For countries vulnerable to climate change as Vietnam, indigenous knowledge (IK) might assist in revealing the values of local people's adaptations to environmental stresses and potentially support decision-making. Despite IK can provide the adaptive capacity of local people's activities within environmental contexts, but it is rapidly vanishing. This study aimed to describe the documentation of IK associated with climate change adaptation of farmers in the Vietnam Mekong Delta (VMD). Methods: We focused on collecting and establishing online access to IK documents through collaboration between IK holders, public sector, collecting institutions, and researchers in the five agro-ecological zones of the VMD. An online IK database for storing IK documents has been designed and implemented based on the web application schema. Results: Through interviews, we gathered IK from farming practices that are well-adapted to climate risks such as floods, droughts, and saltwater intrusions as well as traditional knowledge being used to forecast weather, flood, and saltwater intrusion. The database for storing IK documents has been successfully deployed using free and open-source software. The database currently contains more than 260 IK documents, with their location on agro-ecological zones displayed on a web-based map. Conclusion: We have captured and provided an online access to IK on climate change adaptation of the farmers in the VMD. This research is expected as an initial strategy for long-term sustainable development of the agriculture system in this region.

Joint Fractional Time Allocation and Beamforming for Downlink Multiuser MISO Systems

Nguyen, Van-Dinh,Tuan, Hoang Duong,Duong, Trung Q.,Shin, Oh-Soon,Poor, H. Vincent IEEE 2017 IEEE communications letters Vol.21 No.12

<P>It is well known that the use of traditional transmit beamforming at a base station (BS) to manage interference in serving multiple users is effective only when the number of users is less than the number of transmit antennas at the BS. Non-orthogonal multiple access (NOMA) can improve the throughput of users with poorer channel conditions by compromising their own privacy, because other users with better channel conditions can decode the information of users with poorer channel conditions. NOMA still prefers that the number of users is less than the number of antennas at the BS transmitter. This letter resolves such issues by allocating separate fractional time slots for serving users with similar channel conditions. This enables the BS to serve more users within a time unit while the privacy of each user is preserved. The fractional times and beamforming vectors are jointly optimized to maximize the system’s throughput. An efficient path-following algorithm, which invokes a simple convex quadratic program at each iteration, is proposed for the solution of this challenging optimization problem. Numerical results confirm its versatility.</P>

Thermoelectric Properties of Hot-Pressed Bi-Doped n-Type Polycrystalline SnSe

Nguyen, Van Quang,Nguyen, Thi Huong,Duong, Van Thiet,Lee, Ji Eun,Park, Su-Dong,Song, Jae Yong,Park, Hyun-Min,Duong, Anh Tuan,Cho, Sunglae Springer US 2018 NANOSCALE RESEARCH LETTERS Vol.13 No.1

<P><B>ᅟ</B></P><P>We report on the successful preparation of Bi-doped n-type polycrystalline SnSe by hot-press method. We observed anisotropic transport properties due to the (h00) preferred orientation of grains along the pressing direction. The electrical conductivity perpendicular to the pressing direction is higher than that parallel to the pressing direction, 12.85 and 6.46 S cm<SUP>−1</SUP> at 773 K for SnSe:Bi 8% sample, respectively, while thermal conductivity perpendicular to the pressing direction is higher than that parallel to the pressing direction, 0.81 and 0.60 W m<SUP>−1</SUP> K<SUP>−1</SUP> at 773 K for SnSe:Bi 8% sample, respectively. We observed a bipolar conducting mechanism in our samples leading to n- to p-type transition, whose transition temperature increases with Bi concentration. Our work addressed a possibility to dope polycrystalline SnSe by a hot-pressing process, which may be applied to module applications.</P><P><B>Highlights</B></P><P><P>We have successfully achieved Bi-doped n-type polycrystalline SnSe by the hot-press method.</P><P>We observed anisotropic transport properties due to the [h00] preferred orientation of grains along pressing direction.</P><P>We observed a bipolar conducting mechanism in our samples leading to n- to p-type transition.</P></P><P><B>Electronic supplementary material</B></P><P>The online version of this article (10.1186/s11671-018-2500-y) contains supplementary material, which is available to authorized users.</P>

N-doped Cdot/PtPd nanonetwork hybrid materials as highly efficient electrocatalysts for methanol oxidation and formic acid oxidation reactions

Nguyen, Van-Toan,Tran, Quoc Chinh,Quang, Nguyen Duc,Nguyen, Ngoc-Anh,Bui, Van-Tien,Dao, Van-Duong,Choi, Ho-Suk Elsevier 2018 Journal of alloys and compounds Vol.766 No.-

<P><B>Abstract</B></P> <P>The improvement of the catalytic performance for methanol and formic acid oxidation reactions remains a key issue for the development of a new generation of direct methanol and formic acid fuel cells. This study reports a simple approach, using selective chemical etching for the synthesis of unique nitrogen-doped carbon dot/Pt<SUB>84</SUB>Pd<SUB>16</SUB> (N-Cdot/Pt<SUB>84</SUB>Pd<SUB>16</SUB>) nano-network structure at room temperature with excellent electrocatalytic properties. The obtained nano-network hybrid material exhibits significant enhancement of the electrocatalytic activity for the electro-oxidation reaction of both methanol and formic acid with current densities of 999.0 and 1919.5 mA/mg<SUB>metal</SUB>, respectively, compared with the commercial ones of 751.32 and 806.02 mA/mg<SUB>metal</SUB>, respectively. Furthermore, the N-Cdot/Pt<SUB>84</SUB>Pd<SUB>16</SUB> nano-network hybrid materials exhibit excellent stability and hydrophilic dispersibility at room temperature.</P> <P><B>Highlights</B></P> <P> <UL> <LI> N-Cdot/PtPd nanonetwork hybrid material is synthesized at room temperature. </LI> <LI> A simple coreduction and a selective chemical etching are applied to the synthesis. </LI> <LI> It generates a nano-network structure with excellent electrocatalytic properties. </LI> <LI> N-Cdot functions as a uniform interconnection between the nanohybrid materials. </LI> <LI> The hybrid exhibits significant enhancement of the activity for both MOR and FAOR. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Optimal control of vibration by multiple tuned liquid dampers using Taguchi method

Nguyen Van Khang,Do The Duong,Nguyen Thi Van Huong,Nguyen Duc Thi Thu Dinh,Vu Duc Phuc 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.4

This paper investigates the multiple tuned liquid dampers (MTLD), which consist of a number of MTLD whose first natural frequencies of sloshing are distributed over a certain range around the natural frequency of a structure. The liquid motion in the MTLD as well as the MTLD-structure interaction are numerically simulated using a shallow water-wave theory. An optimal procedure based on Taguchi method is proposed to determine the optimum parameters of MTLD to suppress the vibration amplitude of the considered structure. A number of numerical tests are included to demonstrate and verify the effectiveness of the proposed procedure.

A Magnetization Study of Prussian-blue Analogue Na<SUB>x</SUB>Mn<SUB>y</SUB>[Fe(CN)₆]

Nguyen Van Minh,Phung Kim Phu,Nguyen Minh Thuan,Duong Manh Toan,In-Sang Yang 한국자기학회 2008 한국자기학회 학술연구발표회 논문개요집 Vol.- No.-

Trends in Second-Hand Tobacco Smoke Exposure Levels at Home among Viet Nam School Children Aged 13-15 and Associated Factors

Nguyen, Tuan Lam,Pham, Thi Quynh Nga,Hoang, Van Minh,Kim, Bao Giang,Phan, Thi Hai,Doan, Thu Huyen,Nguyen, Thuy Linh,Duong, Khanh Van,Luong, Ngoc Khue Asian Pacific Journal of Cancer Prevention 2016 Asian Pacific journal of cancer prevention Vol.17 No.no.sup1

Second-hand tobacco smoke (SHS) exposure at home, especially among children, is a serious issue in Viet Nam. During the past decade, much effort has been taken for tobacco control in the country, including various prgorammes aiming to reduce SHS exposure among adults and children. This article analysed trends and factors associated with SHS exposure at home among school children aged 13-15 in Viet Nam, using the Global Youth Tobacco Surveys conducted in 2007 and 2014. Descriptive and inferential statistical methods with logistic regression were applied. Overall, there was a significant reduction in the level of exposure, from 58.5% (95%CI: 57.6-59.3) in 2007 to 47.1% (95%CI: 45.4-48.8) in 2014. Of the associated factors, having one or both parents smoking was significantly associated with the highest odds of SHS exposure at home (OR=5.0; 95%CI: 4.2-6.1). Conversely, having a mother with a college or higher education level was found to be a protective factor (OR=0.5; 95%CI: 0.3-0.8).

Taxus wallichiana Zucc. 현탁세포에서 Jasmonic Acid-Cellulase 복합 Elicitor가 Paclitaxel 생합성에 미치는 영향

Nguyen Ngoc Hoi,Hoang Van Luong,Nguyen Van Long,Vu Binh Duong,변상요(Sang Yo Byun) 한국생물공학회 2010 KSBB Journal Vol.25 No.2

Taxus wallichiana Zucc. 현탁세포배양에서 항암제 paclitaxel 생합성 연구를 수행하였다. 현탁세포배양에서 exponential phase의 최고 생장 속도는 0.14 day-1이었으며 배가시간이 4.96 day이었다. Paclitaxel은 배양초기에 생성되지 않고 exponential phase 말기부터 서서히 생성되어 stationary phase에서도 이어지며 declined phase에서 최고치를 나타내었다. Paclitaxel의 생산을 촉진하기 위하여 elicitor를 사용하였다. 여러 elicitor 중 jasmonic acid와 cellulase가 paclitaxel의 생성을 증가시켰다. Elicitor는 접종과 동시에 투여했을 때 가장 효과가 좋았으며, jasmonic acid와 cellulase의 combination으로 효과가 더욱 증진했는데 각각 투여할 때보다 1.8배 및 3.1배 paclitaxel 생성이 증가되었다. Cell cultures of Taxus wallichiana Zucc. were made to enhance the production of anticancer agent paclitaxel. In suspension cultures, the maximum cell growth rate in exponential growth phase was 0.14 day-1 which was correlated to 4.96 days of cell doubling time. The production of paclitaxel was non-growth associated. The paclitaxel production was started after the exponential growth phase and increased to declined phase where the maximum concentration was observed. Various elicitors were tested to enhance the production of paclitaxel. The combination of two elicitors of jasmonic acid and cellulase increased the production of paclitaxel 1.8 and 3.1 times compared to paclitaxel production by individual elicitor respectively.