Fabrication of Planar Waveguide Chip for Splitting or Combining an Infrared Light Beam

Nguyen Thanh Binh,Nguyen Tat Thanh,Duong Thanh Trung,Nguyen Thanh Huong,Le Quoc Minh 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.52 No.5

Based on hybrid materials of polymethamethyl acrylat, silica and zirconia (ASZ)/Titania (AST), some planar structures of optical power splitter/combiner type 1×N channels were designed and simulated for making masks by using computer software. Splitter chips were then fabricated by using the thin-film sol-gel technique and their structure was formed by using a direct photo-patterning method with UV light and a mask. A conformation of the waveguide was tested with an Alpha-Step IQ system. The waveguide properties of the splitter were measured with a 1550 nm laser source. The experimental results show that the light was transmitted through the chip with a total output efficiency of around 6% and was separated uniformly at the output channels. Based on hybrid materials of polymethamethyl acrylat, silica and zirconia (ASZ)/Titania (AST), some planar structures of optical power splitter/combiner type 1×N channels were designed and simulated for making masks by using computer software. Splitter chips were then fabricated by using the thin-film sol-gel technique and their structure was formed by using a direct photo-patterning method with UV light and a mask. A conformation of the waveguide was tested with an Alpha-Step IQ system. The waveguide properties of the splitter were measured with a 1550 nm laser source. The experimental results show that the light was transmitted through the chip with a total output efficiency of around 6% and was separated uniformly at the output channels.

Visible light-driven photocatalytic degradation of doxycycline using ZnO/g-C₃N₄/biochar composite in aqueous solution

Nguyen Van Hung,Bui Thi Minh Nguyet,Nguyen Huu Nghi,Nguyen Minh Luon,Nguyen Ngoc Bich,Le Van Thanh Son,Nguyen Trung Kien,Dao Ngoc Nhiem,Nguyen Thanh Tuoi,Dinh Quang Khieu 대한환경공학회 2024 Environmental Engineering Research Vol.29 No.4

In the present work, ZnO/g-C₃N₄/biochar was prepared, and it was used for visible-light driven photocatalytic degradation of some colorants (methylene blue, rhodamine B, methyl orange) and some antibiotics (doxycycline, ciprofloxacin, amoxicilline). Biochar was prepared by pyrolysing Phragmites australis biomass. The ZnO/g-C₃N₄/biochar composite was synthesized with the alkaline hydrolysis method. The obtained materials were characterized by X-ray diffraction, scanning electron microscopy, transition electron microscopy, energy dispersive X-ray/elemental mapping, ultraviolet-visible-diffuse reflectance spectroscopy, photoluminescence spectroscopy, nitrogen adsorption/desorption isotherms and X-ray photoelectron spectroscopy. The results show that ZnO nanoparticles with a large surface area are highly dispersed on the g-C₃N₄ particle surface and biochar. The composite exhibits superior photocatalytic degradation ability toward doxycycline, a broad-spectrum antibiotic of the tetracycline compared with individual components (ZnO or g-C₃N₄) and satisfies stability after six treatment cycles. The kinetics and degradation mechanisms of doxycyline were also addressed. In addition, the present catalyst also exhibits the photocatalytic degradation of methylene blue, rhodamine B, methyl orange, ciprofloxacin and amoxicillin in visible-light regions.

Does conventional freezing affect sperm DNA fragmentation?

Le, Minh Tam,Nguyen, Thai Thanh Thi,Nguyen, Tung Thanh,Nguyen, Trung Van,Nguyen, Tam An Thi,Nguyen, Quoc Huy Vu,Cao, Thanh Ngoc The Korean Society for Reproductive Medicine 2019 Clinical and Experimental Reproductive Medicine Vol.46 No.2

Objective: Sperm cryopreservation has been widely used in assisted reproductive technology, as it offers great potential for the treatment of some types of male infertility. However, cryopreservation may result in changes in membrane lipid composition and acrosome status, as well as reductions in sperm motility and viability. This study aimed to evaluate sperm DNA fragmentation damage caused by conventional freezing using the sperm chromatin dispersion test. Methods: In total, 120 fresh human semen samples were frozen by conventional methods, using SpermFreeze Solution as a cryoprotectant. Routine semen analysis and a Halosperm test (using the Halosperm kit) were performed on each sample before freezing and after thawing. Semen parameters and sperm DNA fragmentation were compared between these groups. Results: There was a significant decrease in sperm progressive motility, viability, and normal morphology after conventional freezing (32.78%, 79.58%, and 3.87% vs. 16%, 55.99%, and 2.55%, respectively). The sperm head, midpiece, and tail defect rate increased slightly after freezing. Furthermore, the DNA fragmentation index (DFI) was significantly higher after thawing than before freezing (19.21% prior to freezing vs. 22.23% after thawing). Significant increases in the DFI after cryopreservation were observed in samples with both normal and abnormal motility and morphology, as well as in those with normal viability. Conclusion: Conventional freezing seems to damage some sperm parameters, in particular causing a reduction in sperm DNA integrity.

Anti-inflammatory Asterosaponins from the Starfish <i>Astropecten monacanthus</i>

Thao, Nguyen Phuong,Cuong, Nguyen Xuan,Luyen, Bui Thi Thuy,Thanh, Nguyen Van,Nhiem, Nguyen Xuan,Koh, Young-Sang,Ly, Bui Minh,Nam, Nguyen Hoai,Kiem, Phan Van,Minh, Chau Van,Kim, Young Ho American Chemical Society and American Society of 2013 Journal of natural products Vol.76 No.9

<P>Four new asterosaponins, astrosteriosides A–D (<B>1</B>–<B>3</B> and <B>5</B>), and two known compounds, psilasteroside (<B>4</B>) and marthasteroside B (<B>6</B>), were isolated from the MeOH extract of the edible Vietnamese starfish <I>Astropecten monacanthus</I>. Their structures were elucidated by chemical and spectroscopic methods including FTICRMS and 1D and 2D NMR experiments. The effects of the extracts and isolated compounds on pro-inflammatory cytokines were evaluated by measuring the production of IL-12 p40, IL-6, and TNF-α in LPS-stimulated bone marrow-derived dendritic cells. Compounds <B>1</B>, <B>5</B>, and <B>6</B> exhibited potent anti-inflammatory activity comparable to that of the positive control. Further studies are required to confirm efficacy <I>in vivo</I> and the mechanism of effects. Such potent anti-inflammatory activities render compounds <B>1</B>, <B>5</B>, and <B>6</B> important materials for further applications including complementary inflammation remedies and/or functional foods and nutraceuticals.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jnprdf/2013/jnprdf.2013.76.issue-9/np400492a/production/images/medium/np-2013-00492a_0005.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/np400492a'>ACS Electronic Supporting Info</A></P>

Anti-inflammatory tirucallane saponins from Paramignya scandens.

Phan, Nguyen Huu Toan,Thuan, Nguyen Thi Dieu,Ngoc, Ninh Thi,Thao, Nguyen Phuong,Kim, Sohyun,Koh, Young Sang,Thanh, Nguyen Van,Cuong, Nguyen Xuan,Nam, Nguyen Hoai,Kiem, Phan Van,Kim, Young Ho,Minh, Cha Pharmaceutical Society of Japan 2015 Chemical & pharmaceutical bulletin Vol.63 No.7

<P>Five new tirucallane saponins, paramignyosides A-E (1-5), were isolated from the water fraction of the Paramignya scandens stem and leaves. Their structures were elucidated on the basis of spectroscopic evidence including high-resolution electrospray ionization mass spectrometry (HR-ESI-MS) and one dimensional (1D)- and 2D-NMR. The effects of isolated compounds on pro-inflammatory cytokines were evaluated by measuring the production of interleukin (IL)-12 p40, IL-6, and tumor necrosis factor-α (TNF-α) in lipopolysaccharide (LPS)-stimulated bone marrow-derived dendritic cells (BMDCs). Paramignyoside C (3) exhibited selective and potent inhibitory effect (IC50=5.030.19??M) on the production of IL-12 p40 comparable to that of the positive control, SB203580 (IC50=5.000.16??M). Further studies are required to confirm efficacy in vivo and the mechanism of anti-inflammatory effects.</P>

Perceived Risk of Sharing Other People’s Information on Facebook: The Perspective of Young People in Ho Chi Minh City, Vietnam

Dinh Tien Minh,Tran Ngoc Thuy,Ngo Nguyen Gia Nghi,Nguyen Yen Vy,Nguyen Thi Thanh Lam,Pham Cong Minh KINFORMS 2021 Management Review Vol.16 No.2

In Vietnam, young people are gradually becoming the most accessible objects to social networks. With the development of technology, they usually use online social networks (ONS) as a tool to update information through multimedia content, which may contain other people s information. In different cases, other people s information will be shared and received for different purposes. Therefore, the risk is inevitable and may affect the privacy of individuals whose information is shared, causing turbulence in the community. This study aims to measure impact and find out the factors that influence the willingness of others to share information on social networks in Ho Chi Minh City by examining young people s perceptions that their activities on Facebook may be risky for other people s information. Besides that, the study proposes solutions to avoid possible risks when sharing information with others.

Parenchymal-sparing anatomical hepatectomy based on portal ramification of the right anterior section: A prospective multicenter experience with short-term outcomes

Truong Giang Nguyen,Thanh Khiem Nguyen,Ham Hoi Nguyen,Hong Son Trinh,Tuan Hiep Luong,Minh Trong Nguyen,Van Duy Le,Hai Dang Do,Kieu Hung Nguyen,Van Minh Do,Quang Huy Tran,Cuong Thinh Nguyen 한국간담췌외과학회 2024 Annals of hepato-biliary-pancreatic surgery Vol.28 No.1

Backgrounds/Aims: Parenchymal-sparing anatomical hepatectomy (Ps–AH) based on portal ramification of the right anterior section (RAS) is a new technique to avoid unnecessarily transecting too much liver parenchyma, especially in cases of major anatomical hepatectomy. Methods: We prospectively assessed 26 patients with primary hepatic malignancies having undergone major Ps–AH based on portal ramification of the RAS from August 2018 to August 2022 (48 months). The perioperative indications, clinical data, intra-operative index, pathological postoperative specimens, postoperative complications, and follow-up results were retrospectively evaluated. Results: Among the 26 patients analyzed, there was just one case that had intrahepatic cholangiocarcinoma The preoperative level of α– Fetoprotein was 25.2 ng/mL. All cases (100%) had Child–Pugh A liver function preoperatively. The ventral/dorsal RAS was preserved in 19 and 7 patients, respectively. The mean surgical margin was 6.2 mm. The mean surgical time was 228.5 minutes, while the mean blood loss was 255 mL. In pathology, 5 cases (19.2%) had microvascular invasion, and in the group of HCC patients, 92% of all cases had moderate or poor tumor differentiation. Six cases (23.1%) of postoperative complications were graded over III according to the Clavien–Dindo system, including in three patients resistant ascites or intra-abdominal abscess that required intervention. Conclusions: Parenchymal-sparing anatomical hepatectomy based on portal ramification of the RAS to achieve R0-resection was safe and effective, with favorable short-term outcomes. This technique can be used widely in clinical practice.

Formulation optimization of orally disintegrating tablets containing solid dispersion of felodipine and hydroxypropyl methylcellulose using face-centered central composite design

Nguyen-Thach Tung,Man-Van Hung,Xuan-Minh Vo,Thanh-Hai Nguyen,Thi-Minh-Hue Pham 한국약제학회 2014 Journal of Pharmaceutical Investigation Vol.44 No.2

A novel dosage form integrating solid dispersion(SD) in orally disintegrating tablets (ODTs) wasdeveloped and optimized by the face-centered centralcomposite design to improve poorly soluble property andslow onset action time of felodipine (Fel). SD of Fel andhydroxypropyl methylcellulose E6 was prepared by solventevaporation method. Differential scanning calorimetry andfourier transforms infrared spectroscopy indicated that Feltransformed from crystalline to amorphous state by theformation of hydrogen bond between –N–H in Fel and O–Rin HPMC. The accelerated stability test in 45 C, 75 % RHdemonstrated that the optimized SD was stable in terms ofthe dissolution rate of Fel and thermodynamic property. The ODTs containing SD (Fel:HPMC E6 = 1:3) wereprepared by direct compression technique. The face-centeredcentral composite design with the ODT-SD wasemployed to investigate the effect of mannitol (X1),crospovidone XL (X2) on the ODT-SD disintegration time(Y1), % Fel released after 5 min (Y2) and the ODT-SDfriability (Y3). ANOVA test showed that X2 and X2 * X2had a significant effect on the ODT-SD disintegration time(p\0.05). Meanwhile, the dissolution rate of Fel after5 min did not remarkably depend on any independentvariables (p[0.05). The ODT-SD friability was substantiallyproportional to the amount of mannitol (X1)(p\0.05). The optimized ODT-SD disintegration time, %Fel released after 5 min, and friability were 27.67 s, 88.35and 0.48 %, respectively.

First-Principles Investigation on the Electromechanical Properties of Monolayer 1H Pb-Dichalcogenides

Nguyen Hoang Linh,Nguyen Minh Son,Tran The Quang,Nguyen Van Hoi,Vuong Thanh,Do Van Truong Materials Research Society of Korea 2023 한국재료학회지 Vol.33 No.5

This study uses first-principles calculations to investigate the mechanical properties and effect of strain on the electronic properties of the 2D material 1H-PbX₂ (X: S, Se). Firstly, the stability of the 1H Pb-dichalcogenide structures was evaluated using Born's criteria. The obtained results show that the 1H-PbS₂ material possesses the greatest ideal strength of 3.48 N/m, with 3.68 N/m for 1H-PbSe₂ in biaxial strain. In addition, 1H-PbS₂ and 1H-PbSe₂ are direct semiconductors at equilibrium with band gaps of 2.30 eV and 1.90 eV, respectively. The band gap was investigated and remained almost unchanged under the strain ε_xx but altered significantly at strains ε_yy and ε_bia. At the fracture strain in the biaxial direction (19 %), the band gap of 1H-PbS₂ decreases about 60 %, and that of 1H-PbSe₂ decreases about 50 %. 1H-PbS₂ and 1H-PbSe₂ can convert from direct to indirect semiconductor under the strain ε_yy. Our findings reveal that the two structures have significant potential for application in nanoelectronic devices.

Self-control as an important factor affecting the online learning readiness of Vietnamese medical and health students during the COVID-19 pandemic: a network analysis

Minh Tu Nguyen,Binh Thang Tran,Thanh Gia Nguyen,Minh Tri Phan,Thi Thu Tham Luong,Dinh Duong Le 한국보건의료인국가시험원 2022 보건의료교육평가 Vol.19 No.-

Purpose The current study aimed to use network analysis to investigate medical and health students’ readiness for online learning during the coronavirus disease 2019 (COVID-19) pandemic at the University of Medicine and Pharmacy, Hue University. Methods A questionnaire survey on the students’ readiness for online learning was performed using a Google Form from May 13 to June 22, 2021. In total, 1,377 completed responses were eligible for analysis out of 1,411 participants. The network structure was estimated for readiness scales with 6 factors: computer skills, internet skills, online communication, motivation, self-control, and self-learning. Data were fitted using a Gaussian graphical model with the extended Bayesian information criterion. Results In 1,377 students, a network structure was identified with 6 nodes and no isolated nodes. The top 3 partial correlations were similar in networks for the overall sample and subgroups of gender and grade levels. The self-control node was the strongest for the connection to others, with the highest nodal strength. The change of nodal strength was greatest in online communication for both gender and grade levels. The correlation stability coefficient for nodal strength was achieved for all networks. Conclusion These findings indicated that self-control was the most important factor in students’ readiness network structures for online learning. Therefore, self-control needs to be encouraged during online learning to improve the effectiveness of achieving online learning outcomes for students.