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.

Outcomes of laparoscopic choledochotomy using cholangioscopy via percutaneous-choledochal tube for the treatment of hepatolithiasis and choledocholithiasis: A preliminary Vietnamese study

Loi Van Le,Quang Van Vu,Thanh Van Le,Hieu Trung Le,Khue Kim Dang,Tuan Ngoc Vu,Anh Hoang Ngoc Nguyen,Thang Manh Tran 한국간담췌외과학회 2024 Annals of hepato-biliary-pancreatic surgery Vol.28 No.1

Backgrounds/Aims: Hepatolithiasis and choledocholithiasis are frequent pathologies and unfortunately, with the current treatment strategies, the recurrence incidence is still high. This study aimed to assess the outcomes of laparoscopic choledochotomy using cholangioscopy via the percutaneous-choledochal tube for the treatment of hepatolithiasis and choledocholithiasis in Vietnamese patients. Methods: A cross-sectional study of patients with hepatolithiasis and/or choledocholithiasis who underwent laparoscopic choledochotomy using intraoperative cholangioscopy via percutaneous-choledochal tube at the Department of Hepatopancreatobiliary Surgery, 108 Military Central Hospital, from June 2017 to March 2020. Results: A total of 84 patients were analyzed. Most patients were females (56.0%) with a median age of 55.56 years. Among them, 41.8% of patients had previous abdominal operations, with 33.4% having choledochotomy. All patients underwent successful laparoscopic common bile duct exploration followed by T-tube drainage without needing to convert to open surgery. Most patients (64.3%) had both intrahepatic and extrahepatic stones. The rate of stones ≥ 10 mm in diameter was 64.3%. Biliary strictures were observed in 19.1% of patients during cholangioscopy. Complete removal of stones was achieved in 54.8% of patients. Intraoperative complications were encountered in two patients, but there was no need to change the strategy. The mean operating time was 121.85 ± 30.47 minutes. The early postoperative complication rate was 9.6%, and all patients were managed conservatively. The residual stones were removed through the T-tube tract by subsequent choledochoscopy in 34/38 patients, so the total success rate was 95.2%. Conclusions: Laparoscopic choledochotomy combined with cholangioscopy through the percutaneous-choledochal tube is a safe and effective strategy for hepatolithiasis and/or choledocholithiasis, even in patients with a previous choledochotomy.

WS2–WC–WO3 nano-hollow spheres as an efficient and durable catalyst for hydrogen evolution reaction

Van Nguyen Tuan,Do Ha Huu,Tekalgne Mahider,Van Le Quyet,Nguyen Thang Phan,Hong Sung Hyun,Cho Jin Hyuk,Van Dao Dung,Ahn Sang Hyun,Kim Soo Young 나노기술연구협의회 2021 Nano Convergence Vol.8 No.28

Transition metal dichalcogenides (TMDs), transition metal carbides (TMCs), and transition metal oxides (TMOs) have been widely investigated for electrocatalytic applications owing to their abundant active sites, high stability, good conductivity, and various other fascinating properties. Therefore, the synthesis of composites of TMDs, TMCs, and TMOs is a new avenue for the preparation of efficient electrocatalysts. Herein, we propose a novel low-cost and facile method to prepare TMD–TMC–TMO nano-hollow spheres (WS 2 –WC–WO 3 NH) as an efficient catalyst for the hydrogen evolution reaction (HER). The crystallinity, morphology, chemical bonding, and composition of the composite material were comprehensively investigated using X-ray diffraction, Raman spectroscopy, field emission scanning electron microscopy, and X-ray photoelectron spectroscopy. The results confirmed the successful synthesis of the WS 2 –WC–WO 3 NH spheres. Interestingly, the presence of nitrogen significantly enhanced the electrical conductivity of the hybrid material, facilitating electron transfer during the catalytic process. As a result, the WS 2 –WC–WO 3 NH hybrid exhibited better HER performance than the pure WS 2 nanoflowers, which can be attributed to the synergistic effect of the W–S, W–C, and W–O bonding in the composite. Remarkably, the Tafel slope of the WS 2 –WC–WO 3 NH spheres was 59 mV dec −1 , which is significantly lower than that of the pure WS 2 NFs (82 mV dec −1 ). The results also confirmed the unprecedented stability and superior electrocatalytic performance of the WS 2 –WC–WO 3 NH spheres toward the HER, which opens new avenues for the preparation of low-cost and highly effective materials for energy conversion and storage applications.

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.-

Correction to: WS2–WC–WO3 nano‑hollow spheres as an efficient and durable catalyst for hydrogen evolution reaction

Van Nguyen Tuan,Do Ha Huu,Tekalgne Mahider,Van Le Quyet,Nguyen Thang Phan,Hong Sung Hyun,Cho Jin Hyuk,Van Dao Dung,Ahn Sang Hyun,Kim Soo Young 나노기술연구협의회 2021 Nano Convergence Vol.8 No.33

Following publication of the original article [1], the affiliation of the authors was incorrectly published in the article. The affiliation which was shown in supplementary information is correct. This has been corrected with this erratum.

Effect of hydrothermal time on the structure and property of graphene oxide membrane

Tran Van Khai,Pham Thuy Trang,Le Ngoc Long,Le Van Thang,Tran Duc Chau,Vuong Vinh Dat,Mai Thanh Phong 한양대학교 세라믹연구소 2021 Journal of Ceramic Processing Research Vol.22 No.4

Two dimensional graphene oxide (GO) has potential application in membrane separation owing to its unique structure andphysicochemical properties. In this study, the reduced graphene oxide (rGO) was synthesized from GO via hydrothermaltreatment at 160 oC for 1, 2, 3 and 4 h, and the rGO membranes were prepared on cellulose nitrate supporting membranesby vacuum filtration. The structural change and chemical composition of GO were investigated using X-ray diffraction (XRD),Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM),atomic force microscopy (AFM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS) andcontact angle measurements. The result shows that uniformly intact rGO membranes with good hydrophobicity could beachieved by adjusting the reduction degree of GO through changing the hydrothermal reaction time. The huge improvementof the hydrophobic property of rGO could be attributed to the removal of the most the hydrophilic oxygen-containingfunctional groups on the surface of GO. Additionally, the structure, chemical composition, and d-spacing of the GO can alsobe controlled by adjusting the reduction time. This method holds great potential because it can be prepared in large quantitiesat low cost, and suitable for applications in membrane technologies.

Mental Health Among Healthcare Workers During the COVID-19 Pandemic in Vietnam

Nhan Phuc Thanh Nguyen,Ha Phan Ai Nguyen,Cao Khoa Dang,Minh Tri Phan,Huynh Ho Ngoc Quynh,Van Tuan Le,Chinh Van Dang,Tinh Huu Ho,Van Trong Phan,Van Trong Phan,Thang Phan,Dang Thi Anh Thu 대한예방의학회 2024 예방의학회지 Vol.57 No.1

Objectives: The objective of this study was to characterize mental health issues among Vietnamese healthcare workers (HCWs) and to identify related factors.Methods: A cross-sectional study was conducted with 990 HCWs in 2021. Their mental health status was measured using the Depression, Anxiety, and Stress Scale.Results: In total, 49.9%, 52.3%, and 29.8% of respondents were found to have depression, anxiety, and stress, respectively. The multivariable linear regression model revealed that factors associated with increased anxiety scores included depression scores (β, 0.45; 95% confidence interval [CI], 0.39 to 0.51) and stress scores (β, 0.46; 95% CI, 0.41 to 0.52). Factors associated with increased depression scores included being frontline HCWs (β, 0.57; 95% CI, 0.10 to 1.10), stress scores (β, 0.50; 95% CI, 0.45 to 0.56), and anxiety scores (β, 0.41; 95% CI, 0.36 to 0.47), while working experience was associated with reduced depression scores (β, -0.08; 95% CI, -0.16 to -0.01). Factors associated with increased stress scores included working experience (β, 0.08; 95% CI, 0.00 to 0.16), personal protective equipment interference with daily activities (β, 0.55; 95% CI, 0.07 to 1.00), depression scores (β, 0.54; 95% CI, 0.48 to 0.59), and anxiety scores (β, 0.45; 95% CI, 0.39 to 0.50), while age was associated with reduced stress scores (β, -0.12; 95% CI, -0.20 to -0.05).Conclusions: Specific interventions are necessary to enhance and promote the mental health of HCWs so they can successfully cope with the circumstances of the pandemic.

Dual use of tantalum disulfides as hole and electron extraction layers in organic photovoltaic cells

Le, Quyet Van,Nguyen, Thang Phan,Choi, Kyoung Soon,Cho, Yoon-Ho,Hong, Young Joon,Kim, Soo Young The Royal Society of Chemistry 2014 Physical chemistry chemical physics Vol.16 No.46

<P>UV/ozone treated (UVO-treated) TaS<SUB>2</SUB> and non-treated TaS<SUB>2</SUB> nanosheets are introduced into organic photovoltaic cells (OPVs) as hole extraction layers (HEL) and electron extraction layers (EEL). TaS<SUB>2</SUB> nanosheets are obtained <I>via</I> ultrasonic vibration and size-controlled by centrifugation. Atomic force microscopy (AFM) images reveal that the thickness and lateral size of TaS<SUB>2</SUB> nanosheets are approximately 1 and 70 nm, indicating that uniform and ultrathin TaS<SUB>2</SUB> nanosheets are obtained. The work function of TaS<SUB>2</SUB> increases from 4.4 eV to 4.9–5.1 eV after applying UVO treatment by forming Ta<SUB>2</SUB>O<SUB>5</SUB>. In addition, the power conversion efficiencies of normal OPV with UVO-treated TaS<SUB>2</SUB> and inverted OPV with TaS<SUB>2</SUB> are 3.06 and 2.73%, which are higher than those of OPV without TaS<SUB>2</SUB> (1.56% for normal OPV and 0.22% for inverted OPV). These results indicate that TaS<SUB>2</SUB> is a promising material for HEL and EEL layers in OPVs.</P> <P>Graphic Abstract</P><P>Organic photovoltaic cells with a UVO-treated TaS<SUB>2</SUB> hole extraction layer. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c4cp04412f'> </P>

Improved Stability and Control Analysis Process for Detailed Design Stage of Light Aircraft

Le Viet Thang Nguyen,Nhu Van Nguyen,Jae-Woo Lee,Sangho Kim,Seung-Hyeog Nah 한국항공우주학회 2016 한국항공우주학회 학술발표회 논문집 Vol.2016 No.4

The improved stability and control (S&C) analysis process is developed and presented using wind tunnel test data to investigate the stability and control characteristics of a light aircraft complied with the KAS – VLA subpart B regulations and design requirements at detailed design stage. The enhanced stability and control analysis disciplines are developed for the corresponding KAS – VLA regulations and design requirements to use wind tunnel (W/T) test data, weight and propulsion data in order to improve the reliability of stability and control analysis results. In this study, the improved S&C process is applied for detailed design stage of light aircraft and complied with KAS – VLA to demonstrate the efficiency of the process.

The use of UV/ozone-treated MoS₂ nanosheets for extended air stability in organic photovoltaic cells

Le, Quyet Van,Nguyen, Thang Phan,Jang, Ho Won,Kim, Soo Young The Royal Society of Chemistry 2014 Physical Chemistry Chemical Physics Vol.16 No.26

<P>MoS<SUB>2</SUB> nanosheets obtained through a simple sonication exfoliation method are employed as a hole-extraction layer (HEL) to improve the efficiency and air stability of organic photovoltaic cells (OPVs). The reduction in the wavenumber difference, appearance of a UV-vis peak, and atomic force microscopy images indicate that MoS<SUB>2</SUB> nanosheets are formed through the sonication method. The OPVs with MoS<SUB>2</SUB> layers show a degraded performance with a power conversion efficiency (PCE) of 1.08%, which is lower than that of OPVs without HEL (1.84%). After performing the UV/ozone (UVO) treatment of the MoS<SUB>2</SUB> surface for 15 min, the PCE value increases to 2.44%. Synchrotron radiation photoelectron spectroscopy data show that the work function of MoS<SUB>2</SUB> increases from 4.6 to 4.9 eV upon UVO treatment, suggesting that the increase in the PCE value is caused by the bandgap alignment. Upon inserting poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) between MoS<SUB>2</SUB> and the active layer, the PCE value of the OPV increases to 2.81%, which is comparable with that of the device employing only PEDOT:PSS. Furthermore, the stability of the OPVs is improved significantly when MoS<SUB>2</SUB>/PEDOT:PSS layers are used as the HEL. Therefore, it is considered that the use of UVO-treated MoS<SUB>2</SUB> may improve the stability of OPV cells without degrading the device performance.</P> <P>Graphic Abstract</P><P>A longer lifetime was achieved for devices using MoS<SUB>2</SUB>/PEDOT:PSS layers than for those employing only the PEDOT:PSS layer. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c4cp01598c'> </P>