Using sulfate-functionalized Hf-based metal–organic frameworks as a heterogeneous catalyst for solvent-free synthesis of pyrimido[1,2-a] benzimidazoles via one-pot three-component reaction

Minh-Huy Dinh Dang,Linh Ho Thuy Nguyen,Trang Thi Thu Nguyen,Ngoc Xuan Dat Mai,Phuong Hoang Tran,Tan Le Hoang Doan 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.103 No.-

Functionalized metal–organic frameworks have recently received significant attention in heterogeneouscatalysis applications due to their high catalytic activity. In this work, a sulfate-functionalized Hf-clusterbasedmetal–organic framework was prepared via sulfation of a Hf-MOF, named Hf-BTC, constructed byHf6 clusters and 1,3,5-tricarboxylate linkers. The Hf-BTC-SO4 material was consequently demonstrated tobe an efficiently reusable superacid catalyst for a one-pot three-component reaction of pyrimido[1,2-a]benzimidazoles synthesis. The reaction catalyzed by the sulfated Hf-BTC could be carried out under mildand solvent-free conditions and give superior performance in a wide range of substrates. According todetailed investigation, the good catalytic performance of the sulfated-functionalized MOF likely originatesfrom the high-porosity framework and the high active sites of the functionalized clusters. Importantly, the catalyst could be easy to recover and reuse the functionalized framework several timeswith minor changes in catalytic efficiency.

Raman spectroscopy of Cu doping in Zn_1−xCo_xO diluted magnetic semiconductor

Hoang, Luc Huy,Hien, Nguyen Thi Minh,Hai, Nguyen Hoang,Hai, Pham Van,Khoi, Nguyen The,Yang, In-Sang John Wiley Sons, Ltd. 2009 JOURNAL OF RAMAN SPECTROSCOPY - Vol.40 No.11

<P>The room-temperature ferromagnetism and the Raman spectroscopy of the Cu-doped Zn<SUB>1−x</SUB>Co<SUB>x</SUB>O powders prepared by the sol–gel method are reported. The x-ray diffraction (XRD) data confirmed that the wurtzite structure of ZnO is maintained for ZnO doped with Co below 10 at%. The magnetization–field curves measured at room temperature demonstrated that all Co-doped ZnO powders were paramagnetic. Ferromagnetic ordering is observed for the samples doped with Cu in Zn<SUB>0.98</SUB>Co<SUB>0.02</SUB>O and strongly depends on the concentration of Cu. The relative strength of the second-order LO peak to the first-order one in the Raman spectra, which is related to the carrier concentration, of the Cu-doped Zn<SUB>0.98</SUB>Co<SUB>0.02</SUB>O powder is strongly correlated with the saturation magnetic moment of the system. This seems to be in favor of the Ruderman-Kittel-Kasuya-Yosida (RKKY) or double exchange mechanism of the ferromagnetism in this system. Copyright © 2009 John Wiley & Sons, Ltd.</P> <B>Graphic Abstract</B> <P>The room-temperature ferromagnetism and the Raman spectroscopy data of Cu-doped Zn<SUB>1−x</SUB>Co<SUB>x</SUB>O powders prepared by the sol–gel method are reported. The relative strength of the second-order LO peak to the first-order one in the Raman spectra, which is related to the carrier concentration, of Cu-doped Zn<SUB>0.98</SUB>Co<SUB>0.02</SUB>O powder is strongly correlated with the saturation magnetic moment of the system. <img src='wiley_img/03770486-2009-40-11-JRS2295-gra001.gif' alt='wiley_img/03770486-2009-40-11-JRS2295-gra001'> </P>

An effective combination of reusable Pd@MOF catalyst and deep eutectic solvents for high-performance C–C coupling reaction

Minh-Huy Dinh Dang,Trang Thi Thu Nguyen,Bao Quang Gia Le,Linh Ho Thuy Nguyen,Ngoc Xuan Dat Mai,My Van Nguyen,Phuong Hoang Tran,Tan Le Hoang Doan 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.111 No.-

Pd-incorporated Zr-based metal–organic framework containing sulfone groups, named Pd(II)BUT-11, wassuccessfully prepared by dispersing the sulfone-functionalized MOF in Pd(OAc)2 solution. X-ray diffraction,scanning electron microscopy, N2 isotherm sorption, X-ray photoelectron spectroscopy, and thermogravimetricanalysis were applied to determine the features of the Pd-incorporated MOF. In the catalyticstudies, Pd(II)@BUT-11 was shown to be an efficient heterogeneous catalyst for synthesizing various stilbenederivatives via the cross-coupling Heck reaction with DABCO-derived deep eutectic solvent (DES) asa green solvent. Notably, the catalyst and the solvent could be recovered and reused, with their activityand structure remaining stable throughout several trials. The method provides an alternative solution tothe conventional catalysts and solvents, resulting in a green and efficient stilbene synthesis process. Furthermore, the stilbenes were separated by extraction with ethyl acetate due to the low solubility ofDES with this solvent.

Study Design for the 2016 Baseline Survey of a Health System Strengthening Project in Quoc Oai District, Hanoi, Vietnam

Van Minh Hoang,오주환,Bao Ngoc Nguyen,Le Minh Dat,이종구,Thi Giang Huong Tran,Van Huy Nguyen,이승표,방경숙,조영태,김선영,이화영,Quang Cuong Le,Narshil Choi,Thai Son Dinh,Ngoc Hoat Luu 대한의학회 2019 Journal of Korean medical science Vol.34 No.5

Background: In order to provide essential scientific evidence on the population's health status and social health determinants as well as the current capacity of the health care system in Vietnam to health policy makers and managers, Vietnam Ministry of Health, Hanoi University of Public Health, Hanoi Medical University, and Ho Chi Minh University of Medicine and Pharmacy collaborated with Seoul National University (Korea) and conducted a health system survey in the Quoc Oai district (of Hanoi capital) that represented northern rural Vietnam. Methods: The study design was a cross-sectional study. The survey covered different topics (more than 200 questions) and was administered in three separate questionnaires: 1) Basic information of all household members; 2) Household characteristics; and 3) Individual characteristics. Socio-demographic characteristics among the households and individuals were collected from 2,400 households sampled by multi-stage cluster sampling method: more than 200 questions. Results: The household size of Quoc Oai was larger than the national average and there was no significant difference in gender composition. In addition, the proportions of pre-elderly, age 55–64, and elderly group (65 years old and over) were higher than the national population statistics. In this context, demographic transition has begun in Quoc Oai. Conclusion: This study design description provides the basic information about a baseline survey of a future prospective cohort (as a part of a collaborative project on strengthening the health system in Vietnam) to the prospective data user of this survey.

FGW-FER: Lightweight Facial Expression Recognition with Attention

Huy-Hoang Dinh,Hong-Quan Do,Trung-Tung Doan,Cuong Le,Ngo Xuan Bach,Tu Minh Phuong,Viet-Vu Vu 한국인터넷정보학회 2023 KSII Transactions on Internet and Information Syst Vol.17 No.9

The field of facial expression recognition (FER) has been actively researched to improve human-computer interaction. In recent years, deep learning techniques have gained popularity for addressing FER, with numerous studies proposing end-to-end frameworks that stack or widen significant convolutional neural network layers. While this has led to improved performance, it has also resulted in larger model sizes and longer inference times. To overcome this challenge, our work introduces a novel lightweight model architecture. The architecture incorporates three key factors: Depth-wise Separable Convolution, Residual Block, and Attention Modules. By doing so, we aim to strike a balance between model size, inference speed, and accuracy in FER tasks. Through extensive experimentation on popular benchmark FER datasets, our proposed method has demonstrated promising results. Notably, it stands out due to its substantial reduction in parameter count and faster inference time, while maintaining accuracy levels comparable to other lightweight models discussed in the existing literature.

Genetic diversity of spotted scat (Scatophagus argus) in Vietnam based on COI genes

Huy Van Nguyen,Minh Tu Nguyen,Nghia Duc Vo,Nguyen Thi Thao Phan,Quang Tan Hoang 한국수산과학회 2022 Fisheries and Aquatic Sciences Vol.25 No.12

A spotted scat, Scatophagus argus, has a high nutritional value and is among Asia’s most widely consumed fish species. Thua Thien Hue’s consumption market considers this species to be of high economic value and requires protection and conservation of the population. However, the studies on the identification and genetic diversity of S. argus distributed in Vietnam are still lacking. Therefore, mitochondrial cytochrome c oxidase subunit I (COI) gene was utilized to distinguish different populations and investigate the genetic diversity of two populations of S. argus from Tam Giang lagoon, Thua Thien Hue province (n = 31) and Ca Mau province (n = 14). The sequencing results indicated 13 distinct haplotypes among 45 sequences. Five single nucleotide polymorphisms were observed to distinguish Hue spotted scat population. The S. argus population in Ca Mau province was higher haplotype diversity (Hd) and nucleotide diversity (π) than those of Thua Thien Hue province, which demonstrates that there are minor differences between haplotypes. There were genetic distances ranging from 0%–4% within the populations and 6.67% between the two populations. In addition to the sequencing, the comparison of morphology, biology, culture, and the growth rate was sufficient to distinguish the spotted scat S. argus in Thua Thien Hue from Ca Mau.

Appropriation of Protocol for Laparoscopic Pancreaticoduodenectomy in Treatment of Periampullary Cancer

( Minh Hai Pham ),( Quan Anh Tuan Le ),( Hoang Bac Nguyen ),( Quang Hung Vu ),( Thai Ngoc Huy Tran ),( Hang Dang Khoa N Guyen ),( Thi Ngoc Sang Duong ),( Van Toan Tran ) 대한간학회 2020 춘·추계 학술대회 (KASL) Vol.2020 No.1

Aims: Laparoscopic pancreaticoduodenectomy (LPD) is considered as a safe and effective procedure in well - selected patients and appropriate surgical technique. Our aim is to evaluate suitability of using protocol for LPD in treatment of periampullary cancer at a single team. Methods: case series Results: Indication for LPD included 37 cases with resectable tumors which were classified basing on NCCN. All witness evaluation risk of complications with PREPARE score, ASA and evaluation risk of postoperative pancreatic fistula (POPF) with FRS classification. There were 2 open conversions because of vein resections, accounting for 5.4%. Standard lymphadenectomy was performed in all of 37 cases. In term of PREPARE score, major complications (Clavien - Dindo >= III) were 17.8%, 0% and 0% (5/28, 0/5 and 0/2 cases) in low risk, intermediate risk and high risk group, respectively. All of cases had ASA I or II. POPF happened 11.1% (1/9), 4.1% (1/24) and 50% (1/2) in low risk, intermediate risk and high risk group, respectively. Frozen section was needed for R0 margin. Retrieved lymph nodes was 8 - 18 with 12 lymph nodes in average. Conclusions: Indication for LPD with resectable tumors is acceptable. ASA I or II is a safe measure to select patient for LPD. FRS classification shows appropriation to evaluate risk of POPF.

Healthcare Workers’ Knowledge and Attitudes Regarding the World Health Organization’s “My 5 Moments for Hand Hygiene”: Evidence From a Vietnamese Central General Hospital

Huy Van Nguyen,Hieu Trung Tran,Long Quynh Khuong,Thanh Van Nguyen,Na Thi Nhi Ho,An Thi Minh Dao,Minh Van Hoang 대한예방의학회 2020 예방의학회지 Vol.53 No.4

Objectives: Although the World Health Organization (WHO) initiative “My 5 Moments for Hand Hygiene” has been lauded as effective in preventing hospital-associated infections, little is known about healthcare workers (HCWs)’ hand hygiene behavior. In this study, we sought to assess knowledge and attitudes towards the concepts in this initiative, as well as associated factors, among Vietnamese HCWs at a general hospital. Methods: A structured questionnaire was administered to HCWs at a central Vietnamese general hospital in 2015. Multiple logistic regression analysis was used to identify factors associated with HCWs’ knowledge and attitudes towards hand hygiene. Results: Of 120 respondents, 65.8% and 67.5% demonstrated appropriate knowledge and a positive attitude, respectively, regarding all 5 hand hygiene moments. Logistic regression indicated better knowledge of hand hygiene in workers who were over 30 years old, who were direct HCWs (rather than managers), who had frequent access to clinical information, and who received their clinical information from training. Those who worked in infectious and tropical disease wards, who had frequent access to clinical information, and who received information from training were more likely to have a positive attitude towards hand hygiene than their counterparts. Conclusions: Although many Vietnamese HCWs displayed moderate knowledge and positive attitudes towards the WHO hand hygiene guidelines, a key gap remained. Regular education and training programs are needed to increase knowledge and to improve attitudes and practices towards hand hygiene. Furthermor

Unstructured Discrete Ordinates Method Based on Radial Basis Function Approximation

Quang Huy Khuat,Sy Minh Tuan Hoang,우명현,김재현,김종경 한국물리학회 2019 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.75 No.1

Numerical treatment of the boundary value problem with meshfree methods has been a popular research area in recent years. In the nuclear transport field, several applications of meshfree methods are employed to develop a solution for the neutron diffusion and transport equations. Among the meshfree methods, which based on radial basis function (RBF) approximation exhibits more advantages than others. By applying the RBF approximation, a flexible technique for discretizing the spatial variable of the neutron transport equation is provided without any requirements related to the shape of the unstructured mesh or the number of spatial dimensions. However, use of the RBF approximation without specified constraints on the number of data points used for constructing the approximation function may cause instability in the discrete equation system. In addition, it decreases the accuracy of the numerical solution near the geometric boundary. In this study, a numerical method is developed to solve the discrete ordinates equation (S$_{\rm N}$) on unstructured mesh for neutron transport. Several benchmarks are implemented to evaluate the efficiency of the proposed method. Results are compared with analytical and reference results from the standard S$_{\rm N}$ method. The proposed method provides a stable and accurate solution for the transport problem with curved boundaries.

적응형 회로를 이용한 무선전력전송 효율증가

이승규,Hoang Minh Huy,변영재 대한전자공학회 2011 전자공학회지 Vol.38 No.10