Sleep Quality and Poor Sleep-related Factors Among Healthcare Workers During the COVID-19 Pandemic in Vietnam

Thang Phan,Ha Phan Ai Nguyen,Cao Khoa Dang,Minh Tri Phan,Vu Thanh Nguyen,Van Tuan Le,Binh Thang Tran,Chinh Van Dang,Tinh Huu Ho,Minh Tu Nguyen,Thang Van Dinh,Van Trong Phan,Binh Thai Dang,Huynh Ho Ngo The Korean Society for Preventive Medicine 2023 예방의학회지 Vol.56 No.4

Objectives: The coronavirus disease 2019 (COVID-19) pandemic has increased the workload of healthcare workers (HCWs), impacting their health. This study aimed to assess sleep quality using the Pittsburgh Sleep Quality Index (PSQI) and identify factors associated with poor sleep among HCWs in Vietnam during the COVID-19 pandemic. Methods: In this cross-sectional study, 1000 frontline HCWs were recruited from various healthcare facilities in Vietnam between October 2021 and November 2021. Data were collected using a 3-part self-administered questionnaire, which covered demographics, sleep quality, and factors related to poor sleep. Poor sleep quality was defined as a total PSQI score of 5 or higher. Results: Participants' mean age was 33.20±6.81 years (range, 20.0-61.0), and 63.0% were women. The median work experience was 8.54±6.30 years. Approximately 6.3% had chronic comorbidities, such as hypertension and diabetes mellitus. About 59.5% were directly responsible for patient care and treatment, while 7.1% worked in tracing and sampling. A total of 73.8% reported poor sleep quality. Multivariate logistic regression revealed significant associations between poor sleep quality and the presence of chronic comorbidities (odds ratio [OR], 2.34; 95% confidence interval [CI], 1.17 to 5.24), being a frontline HCW directly involved in patient care and treatment (OR, 1.59; 95% CI, 1.16 to 2.16), increased working hours (OR, 1.84; 95% CI,1.37 to 2.48), and a higher frequency of encountering critically ill and dying patients (OR, 1.42; 95% CI, 1.03 to 1.95). Conclusions: The high prevalence of poor sleep among HCWs in Vietnam during the COVID-19 pandemic was similar to that in other countries. Working conditions should be adjusted to improve sleep quality among this population.

Green and direct functionalization of poly (ethylene glycol) grafted polymers onto single walled carbon nanotubes: Effective nanocarrier for doxorubicin delivery

Xuan Thang Cao,Maheshkumar Prakash Patil,Quoc Thang Phan,Cuong M.Q. Le,Byung-Hyun Ahn,GUN-DO KIM,임권택 한국공업화학회 2020 Journal of Industrial and Engineering Chemistry Vol.83 No.-

This paper reports a green and direct functionalization of poly(ethylene glycol)-graft-[furfuryl-graft-(poly(styrene-alt-maleic anhydride))] (PEG-PSMF) on the surface of single walled carbon nanotubes (SWCNTs)in aqueous media through Diels-Alder (DA) click reaction. Firstly, novel PEG grafted, furfurylfunctionalized copolymers were prepared by RAFT polymerization followed by ring opening reactions. The functional copolymer was simply grafted on SWCNTs by DA reaction at room temperature underultrasonication. The resulting hybrid materials were characterized by 1H NMR, GPC, UV–vis, FT-IR, TGA,TEM, and DLS. The hybrid materials possessed a high drug loading capacity (DLC) of doxorubicin (DOX),which could reach up to 279.9 wt.% of DLC. Moreover, in vitro drug release profiles showed that drugrelease rate at pH 5.5 under an acidic condition of tumor cell microenvironment was much higher than atpH 7.4 of the physiological condition. MTT assays demonstrated that the hybrid materials did not haveany practical cytotoxicity against the normal HEK293 cell line, while drug loaded hybrids displayed a highantitumor activity towards HeLa cancer cells. This strategy offers a promising SWCNT-based drug carrierfor tumor-targeted chemotherapy.

Controller design of a bi-directional dc-dc converter for charge-discharge of a 3 kW PCS battery

Van Thang Do(도반탕),Chang- Soon Kim(김창순),Dinh- Vuong Le(레딘브엉),Tat- Thang Le(레덧탕),Minwon Park(박민원),In- Keun Yu(유인근) 대한전기학회 2018 대한전기학회 학술대회 논문집 Vol.2018 No.-

Incorporation of ICRP-116 Eye Model into ICRP Reference Polygonal Surface Phantoms

Thang Tat Nguyen,Yeon Soo Yeom,Min Cheol Han,Zhao Jun Wang,Han Sung Kim,Chan Hyeong Kim 대한방사선방어학회 2015 대한방사선방어학회 학술발표회 논문요약집 Vol.2015 No.04

Adult-to-Adult Right Lobe Graft Living Donor Liver Transplantation for Acute-on-Chronic Liver Failure: An Initial Single-Center Experience in Vietnam

( Thang Tran Manh ) 대한간학회 2024 춘·추계 학술대회 (The Liver Week) Vol.2024 No.1

Free vibration characteristics of sigmoid-functionally graded plates reinforced by longitudinal and transversal stiffeners

Thang, Pham Toan,Lee, Jaehong Elsevier 2018 Ocean engineering Vol.148 No.-

<P><B>Abstract</B></P> <P>The main objective of this research paper is to investigate the positive influence of the stiffeners on the vibration of functionally graded plates based on an exact approach via Navier solution. The plate is reinforced by stiffeners in both longitudinal and transversal directions. The material properties of functionally graded materials (FGMs) media are distributed across the thickness based on a sigmoid-law form and are assumed to be temperature-dependent. By using the Hamilton's principle and the classical plate theory (CPT), the governing equations of motion are obtained. Based on the Navier solution, an exact solution is proposed for natural frequencies of simply supported rectangular plates. In addition, the effects of related parameters on natural frequencies are also addressed in detail. Finally, numerical examples are presented and compared with existing results.</P> <P><B>Highlights</B></P> <P> <UL> <LI> An exact solution for free vibration analysis. </LI> <LI> Plates are reinforced by longitudinal and transversal stiffeners. </LI> <LI> Based on the Kirchhoff's plate theory. </LI> <LI> Plates are made of sigmoid-functionally graded material (S-FGM). </LI> </UL> </P>

Closed-form expression for nonlinear analysis of imperfect sigmoid-FGM plates with variable thickness resting on elastic medium

Thang, Pham-Toan,Nguyen-Thoi, T.,Lee, Jaehong Elsevier 2016 COMPOSITE STRUCTURES -BARKING THEN OXFORD- Vol.143 No.-

<P><B>Abstract</B></P> <P>With the aim of reducing the weight of structures, functionally graded materials (FGM) plates with variable thickness have been widely used in various engineering applications such as aeronautical, mechanical and ocean structures. However so far, the analytical approaches for analyzing the instability behaviors of FGM plates with variable thickness are still somehow limited in the literature. The paper hence presents an analytical approach to investigate the influences of variable thickness on buckling and postbuckling behavior of imperfect sigmoid FGM (S-FGM) plates resting on elastic medium subjected to compressive loading. The material properties of S-FGM plates are assumed to be graded in the thickness direction according to a simple power law distribution in terms of the volume fractions of the constituents. Governing equations are based on the classical plate theory with von Karman-type geometric nonlinearity. The initial geometrical imperfections of plates are also accounted. By using the Galerkin procedure and the Airy stress function, the resulting equations are solved to obtain the closed form expressions for nonlinear equilibrium paths. The effects of power-law indices, coefficients of foundation, initial geometrical imperfections and geometrical parameters on nonlinear stability of plates are comprehensively investigated. The results reveal that the variable thickness of plate has a significant effect on the buckling behavior of S-FGM plates under compression loading.</P>

Mn-doped (Ba, Y)Fe12O19 hexaferrites: Crystal structure and oxidation states of Mn and Fe

Thang P.D.,Ho T.A.,Dang N.T.,Lee B.W.,Phan T.L.,Manh T.V.,Kim D.H.,Yang D.S. 한국물리학회 2020 Current Applied Physics Vol.20 No.11

We have fabricated Ba0.95Y0.05Fe12-xMnxO19 samples with large Mn-doping amounts of x = 4 and 6, using the mechanical milling and heat treatment. X-ray diffraction analysis indicated the samples crystallized in the M-type hexaferrite structure. The Mn doping caused the modification, shift and broadening of some characteristic phonon-vibration modes, which were recorded by Raman spectroscopy. This is due to an incorporation of Mn ions into the M-type structure that disorders the periodic lattice and changes symmetry. Basing on X-ray absorption spectroscopy, we have found Fe in all samples stable with an oxidation state 3+ (Fe3+). Though Mn2+ and Mn3+ ions coexist, the concentration of Mn2+ in x = 4 is larger than that in x = 6. The analysis of Fouriertransform spectra have demonstrated the replacement of Mn2+,3+ ions for Fe3+ in the M-type structure. The sites of Mn2+,3+ ions in this structure have been discussed.

Analysis and Design of Grid-Connected Photovoltaic Systems With Multiple-Integrated Converters and a Pseudo-DC-Link Inverter

Thang, T. V.,Thao, N. M.,Jong-Ho Jang,Joung-Hu Park IEEE 2014 IEEE transactions on industrial electronics Vol.61 No.7

<P>An architecture of multiple-integrated converter modules sharing an unfolding full-bridge inverter with a pseudo dc link (MIPs) is proposed for grid-connected photovoltaic systems in this paper. The proposed configuration can improve the power conversion, the control circuit complexity, and the cost competitiveness. The proposed MIP is composed of distributed flyback dc-dc converters (DFCs) and an unfolding full-bridge inverter with an ac filter. The DFCs can eliminate the shading effect by using the individual maximum power point tracking. In conventional flyback-type single-phase utility-interactive inverters, discontinuous conduction mode and boundary conduction mode are popular because of the inherent constant current-source characteristics more desirable for grid connection and of the simple procedures for the controller design. However, the operating mode suffers from a large current stress of the circuit components, which leads to the low power efficiency. To avoid this, the DFCs operate under continuous conduction mode that allows reduced current stresses and increased power efficiency, as well as low material cost. The current control loop of the converters employs primary-side regulation contributing to improvement of dynamics as well as the cost reduction significantly due to the elimination of the high-linearity photocoupler device. Development of a new dc-current loop that maintains the level of dc-current injection into the grid within the levels stipulated by IEEE 1547 will be dealt as well. The performance validation of the proposed design is confirmed by experimental results of a 200-W hardware prototype.</P>

Plasma Osmolality Controls Dry Forage Intake in Large-type Goats

Thang, Tran Van,Sunagawa, Katsunori,Nagamine, Itsuki,Ogura, Go Asian Australasian Association of Animal Productio 2011 Animal Bioscience Vol.24 No.8

In large-type goats that were fed on dry forage twice daily, dry forage intake was markedly suppressed after 40 min of feeding had elapsed. The objective of this study was to clarify whether or not increases in plasma osmolality and subsequent thirst sensations produced by dry forage feeding suppress dry forage intake. Eight large-type male esophageal- and ruminal-fistulated goats (crossbred Japanese Saanen/Nubian, aged 3 to 6 years, weighing $72.3{\pm}2.74$ kg) were used in two experiments conducted under sham feeding conditions. The animals were fed ad libitum a diet of roughly crushed alfalfa hay cubes for 2 h from 10:00 to 12:00 h during two experiments. Water was withheld during feeding in both experiments but was available for a period of 30 min after completion of the 2 h feeding period. In experiment 1, an intraruminal infusion of artificial parotid saliva (RIAPS) in the control replenished saliva lost via the esophageal fistula and an intraruminal infusion of hypertonic solution (RIHS) in the treatment was carried out in order to reproduce the effects of changing salt content due to feed entering the rumen. In experiment 2, the RIHS control was conducted in the same manner as the RIHS treatment of experiment 1. The treatment group consisted of RIHS-with an intravenous infusion of artificial mixed saliva (VIAMS) treatment that was carried out for 3 h to prevent increases in plasma osmolality during feeding. The results of the RIHS treatment in experiment 1 showed that ruminal fluid osmolality increased and then an increase in plasma osmolality was observed. This resulted in the production of thirst sensations and the reduction of cumulative dry forage intake to 43.3% (p<0.05) of the RIAPS control. The results of the RIHS-VIAMS treatment in experiment 2 indicated that ruminal fluid osmolality was the same as the RIHS control but plasma osmolality significantly decreased, and thirst level was markedly reduced. This caused a significant increase of 31.4% (p<0.05) in cumulative dry forage intake in the RIHS-VIAMS treatment compared to the RIHS control. These results indicate that increases in ruminal fluid osmolality during dry forage feeding indirectly suppresses dry forage intake by causing an increase in plasma osmolality and subsequently inducing thirst sensations. The results of the present study suggest that marked decreases in dry forage intake after 40 min of feeding are caused by increases in plasma osmolality and subsequent thirst sensations produced by dry forage feeding.