An Advanced Celestial Method to Determine Ship’s Position by Simultaneous Observation of Altitude and Azimuth of the Sun

Thai-Duong NGUYEN,Tu-Nam LUONG 국제이네비해양경제학회 2021 International Journal of e-Navigation and Maritime Vol.16 No.1

A ship’s position as determined by the observation of celestial bodies is a traditional method with important advantages, such as reliability, independence and a low cost. Global satellite navigation systems, with many outstanding advantages in terms of accuracy and continuity, have become the main method of ship positioning in offshore navigation. Ship positioning using celestial body observation is still a backup method in the event of unusual incidents. Currently, during the daytime, it is only possible to apply the celestial navigation method to determine the ship’s position by observing the altitude of the sun. In order to reduce geometrical errors, this traditional method requires time for a certain change of the azimuth of the sun and therefore depends much on estimated errors and the effects of external conditions. Moreover, the basic requirement of the backup method is to provide a ship position quickly during offshore navigation, without the position being determined by a global satellite positioning system. To overcome the above limitations, the paper proposes a new approach to determine a ship's position by simultaneously observing the altitude and azimuth of the sun. A program for calculating the position of a ship with high reliability and applicability based on the new algorithm is also devised and shown to be highly effective in practice.

Recent advances in Alzheimer’s disease pathogenesis and therapeutics from an immune perspective

Nguyen Thai-Duong,Dang Loi Nguyen,Jang Jung-Hee,박소연 한국약제학회 2023 Journal of Pharmaceutical Investigation Vol.53 No.5

Background The prevalence of Alzheimer’s disease, the most common type of dementia, is continuously increasing. Many recent reports have indicated that immune-related mechanisms play a vital role in Alzheimer’s disease pathogenesis, such that the imbalance between the immune response and central nervous system leads to neuroinflammation. Area covered The inflammatory response in Alzheimer’s disease is a “double-edged sword”. Neuroinflammation protects neuronal cells in the initial stages of Alzheimer’s disease, while sustained inflammation promotes neurodegeneration. Alterations in the peripheral immune system, such as increased inflammation, lead to the activation of the central immune response, which in turn causes neuroinflammation and neuronal damage. Additionally, an imbalance between pro- and anti-inflammatory cytokines, which are secreted by the central and peripheral immune systems, induces complex immune responses and contributes to Alzheimer’s disease pathogenesis. In this review, we aimed to summarize our current knowledge of the role of the immune system in Alzheimer’s disease pathology. We performed an in-depth investigation on the contribution of each immune system component to Alzheimer’s disease progression at different disease stages. More importantly, we discuss novel immune-related therapeutic strategies for Alzheimer’s disease treatment currently being investigated via clinical trials. Expert opinion The scrutinized observations of immune responses in different brain regions at various stages of Alzheimer’s disease might help identify potential treatment strategies for Alzheimer’s disease. The modulation of immune components in the brain by targeting cytokines and other factors, which compromise immune response and neuroinflammation, is recommended as a promising alternative for Alzheimer’s disease treatment. Clinical trials are currently investigating the efficacies of numerous vaccines and monoclonal antibodies targeting amyloid beta peptide and tau protein for Alzheimer’s disease treatment. Moreover, aducanumab and lecanemab were approved by the Food and Drug Administration as monoclonal antibody-based drugs for Alzheimer’s disease treatment in 2021 and 2023, respectively. However, these drugs are effective only against mild symptoms due to the irreversible neuronal damage found in patients with Alzheimer’s disease progression. In addition, side effects including amyloid-related imaging abnormalities (such as vasogenic edema, microhemorrhages, and hemosiderosis) were reported in patients undergoing Alzheimer’s disease treatment using monoclonal antibodies. Thus, the future development of therapeutic agents for Alzheimer’s disease requires more sophisticated and multi-plunged approaches considering various biomarkers and immune landscapes characterizing the different stages of Alzheimer’s disease.

Influence of MoS2 deposition time on the photocatalytic activity of MoS2/ V, N co-doped TiO2 heterostructure thin film in the visible light region

Hang Nguyen Thai Phung,Nguyen Duc Truong,Phuong Ai Duong,Le Vu Tuan Hung 한국물리학회 2018 Current Applied Physics Vol.18 No.6

Electron-hole separation and a narrow band-gap are essential steps to obtain efficient photocatalysis, towards which the use of co-catalysts or co-doped-TiO2 photocatalysts has become a widely used strategy. In this article, the combination of MoS2 and co-doping of V, N is the goal to achieve high performance photocatalysts. We synthesized MoS2/V, N co-doped TiO2 heterostructure thin film by solgel and chemical bath deposition methods. Herein, we investigated the influence of deposition time of MoS2 layer on visible-photocatalytic activity of the obtained samples. The thin films were characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy and UVevis spectroscopy techniques. Visible-photocatalytic activity of these samples were evaluated on the removal of methylene blue (MB) under visible light irradiation. The results show that the aforementioned heterostructure thin films have better photocatalytic activities than those of TiO2, MoS2 and V, N codoped TiO2 counterparts in visible light region. The mechanism for increasing visible-photocatalytic property of the heterostructure thin films is discussed in detail. We find that MoS2/V, N co-doped TiO2 heterostructure thin film at MoS2 deposition time of 45-min shows the highest photocatalytic performance in the visible light region with MB photodegradation rate about 99% for 150 min and the degradation rate constant is 2.06 times higher than that of V and N co-doped TiO2 counterpart.

The Influence of Hydrotalcite Intercalated with Benzoate on UV Stability of Acrylic Coating

Thuy Duong Nguyen,Anh Son Nguyen,Thu Thuy Thai,Gia Vu Pham,Thi Xuan Hang To,Marie-Georges Olivier 한국부식방식학회 2020 Corrosion Science and Technology Vol.19 No.1

It is important to realize that benzoate was intercalated into hydrotalcite (HTC-Bz) by the co-precipitationmethod. In this case, acrylic coating with 0.5 wt% HTC-Bz was deposited on carbon steel using the spincoating method. Next, the HTC-Bz structure was characterized by Field emission scanning electron microscopy(FESEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR). In fact, an ultravioletvision spectroscopy (UV-Vis) was used to determine the benzoate content in HTC-Bz, and the UV absorptionability of HTC-Bz. Using electrochemical techniques, water contact angle measurement, and thermal-gravimetricanalysis, we compared the protective properties before and after QUV test, hydrophobicity and the thermalstability of acrylic coating containing HTC-Bz. The obtained results showed that HTC-Bz with a plate-likestructure was successfully synthesized; benzoate was intercalated into the interlayer of hydrotalcite witha concentration of 28 wt%. Additionally, it was noted that HTC-Bz has an UV absorption peak at 225nm. In conclusion, the addition of HTC-Bz enhanced the UV stability, hydrophobicity and the thermal stabilityof acrylic coating.

Effect of Zn/Al Cation Ratio on Corrosion Inhibition Capabilities of Hydrotalcites Containing Benzoate Against Carbon Steel

Thuy Duong Nguyen,To Thi Xuan Hang,Thu Thuy Pham,Anh Son Nguyen,Thu Thuy Thai,Gia Vu Pham,Ngoc Bach Ta 한국부식방식학회 2022 Corrosion Science and Technology Vol.21 No.6

Corrosion inhibitors based on Zn-Al hydrotalcites containing benzoate (ZnAlHB) with different molar ratios of Zn/Al were prepared with a co-precipitation process. Compositions and structures of the resulting hydrotalcites were studied with suitable spectroscopic methods such as inductively coupled plasma mass spectrometry (ICP-MS), ultraviolet-visible spectrophotometry (UV-Vis), scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and surface zeta potential measurements, respectively. Results of physico-chemical studies showed that crystallite sizes, compositions of products, and surface electrical properties were significantly changed when the molar ratio of Zn/Al was increased. The release of benzoate from hydrotalcites also differed slightly among samples. Anticorrosion abilities of hydrotalcites intercalated with benzoate at a concentration of 3 g/L on carbon steel were analyzed using electrochemical impedance spectroscopy (EIS), polarization curve, energy-dispersive X-ray spectroscopy (EDX), and SEM. Corrosion inhibition abilities of benzoate modified hydrotalcites in 0.1 M NaCl showed an upward trend with increasing Zn/Al ratio. The reason for the dependence of corrosion resistance on the Zn/Al ratio was discussed, including changes in the microstructure of hydrotalcites such as crystal size, density, uniformity, and formation of ZnO.

Effect of Co-Doping and Tri-Doping with Transition Metals and a Nonmetal on Photocatalytic Activity in Visible Light of TiO2 Thin Film

Hang Nguyen Thai Phung,Van Nguyen Khanh Tran,Phuong Ai Duong,Hung Vu Tuan Le,Nguyen Duc Truong 한국물리학회 2017 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.70 No.11

Mono, co- and tri-doped TiO2 thin films with the transition metals (vanadium and/or chrominium) and a nonmetal (nitrogen) have been fabricated by sol-gel method. X-ray diffraction results clearly reveal anatase crystal structure for all obtained samples and doping with any dopants doesn’t change the anatase phase of TiO2. Compared to TiO2, three types of doped TiO2 thin films exhibit a red-shift in the absorption edge and have much better photocatalytic properties for methylene blue degradation in visible light region. The maximum visible-photocatalytic performance was achieved for tri-doped TiO2 sample. The mechanism for enhancing visible-photocatalytic activity of co-doped and tri-doped TiO2 thin films was also examined.

Facile synthesis of multifunctional Ag/Fe3O4-CS nanocomposites for antibacterial and hyperthermic applications

Ngoan Thi Nguyen,Dai Lam Tran,Duc Cuong Nguyen,Thai Loc Nguyen,Thi Cham Ba,Binh Hai Nguyen,Thi Duong Ba,Nam Hong Pham,Dzung Tuan Nguyen,Thai Hoa Tran,Gia Dien Pham 한국물리학회 2015 Current Applied Physics Vol.15 No.11

Nanocomposites containing two or more functional constituents are attractive candidates for advanced nanomaterials. In this study, multifunctional Ag/Fe3O4-CS nanocomposites were successfully prepared, using chitosan as a stabilizing and cross-linking agent. The as-synthesized nanocomposites were characterized by Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), X-ray diffraction (XRD), Energy-dispersive X-ray spectroscopy (EDS), UVevisible spectrophotometer (UVeVis) and vibrating sample magnetometer (VSM). The results demonstrated that Ag/Fe3O4-CS composite nanoparticles (NPs) were composed of parent components, Fe3O4 and Ag NPs, which were uniformly dispersed in the chitosan matrix. The hybrid NPs exhibited strong antibacterial property against Pseudomonas aeruginosa. With high magnetization value (67 emu/g), the synthesized Ag/Fe3O4-CS composite can be easily separated or recycled in potential biomedical applications. Furthermore, the results showed that the multicomponent hybrid nanostructures appeared to be the promising material for local hyperthermia, which can be used as thermoseeds for localized hyperthermia treatment of cancers.

Effects of Trang Phuc Linh Plus-Food Supplement on Irritable Bowel Syndrome Induced by Mustard Oil

Thong T. Nguyen,Duong T. Dau,Dung C. Nguyen,Huong T.T.G. Nguyen,Phuong T.B. Ngo,Thai Q. Nguyen,Bo Han,Ba X. Hoang 한국식품영양과학회 2017 Journal of medicinal food Vol.20 No.4

Trang phuc linh plus (TPLP) is a food supplement product derived from dried extracts of herbal agents Atractylodes macrocephala, Poria cocos, Paeonia lactiflora, Phellodendron amurense, and added lactobacillus fermentum lysate (ImmuneGamma®) and 5-hydroxytryptophan. TPLP is a functional food used as adjunctive treatment for treating irritable bowel syndrome (IBS). However the biological effect and its mechanism of action in IBS have not been elucidated. In this study, we aimed to determine the pharmacological activities and mode of action of TPLP on IBS animal models. Mice were given a single administration of 5% mustard oil (MO) intracollonically. Acute colitis induction by MO resulted in later development of an IBS-like accelerated upper gastrointestinal transit in mice. Mice were treated with different does of TPLP and controls. Results showed that TPLP at the dose of 654 mg/kg/day given orally significantly decreased intestinal motility (IM) compared with the control animals. The effect was similar to Duspatalin (80 mg/kg/day) (Mebeverine Hydrochloride, an antispasmodic that helps to relieve the pain and discomfort associated with gastrointestinal spasms). Increased TPLP dose (1962 mg/kg/day) had a better effect on relief of IM than Duspatalin (80 mg/kg/day). TPLP also reduced peristalsis frequency and decreased fluid volume and electrolytes excretion in intestine tested in ex vivo models. Overall, TPLP may be an effective nutraceutical supplement for IBS.

Thinning and drilling laser-assisted hatching in thawed embryo transfer: A randomized controlled trial

Le, Minh Tam,Nguyen, Thi Tam An,Nguyen, Thi Thai Thanh,Nguyen, Van Trung,Le, Dinh Duong,Nguyen, Vu Quoc Huy,Cao, Ngoc Thanh,Aints, Alar,Salumets, Andres The Korean Society for Reproductive Medicine 2018 Clinical and Experimental Reproductive Medicine Vol.45 No.3

Objective: In frozen and thawed embryos, the zona pellucida (ZP) can be damaged due to hardening. Laser-assisted hatching (LAH) of embryos can increase the pregnancy rate. This study compared thinning and drilling of the ZP before frozen embryo transfer (FET). Methods: Patients were randomly allocated into two groups for LAH using thinning or drilling on day 2 after thawing. Twenty-five percent of the ZP circumference and 50% of the ZP thickness was removed in the thinning group, and a hole $40{\mu}m$ in diameter was made in the drilling group. Results: A total of 171 in vitro fertilization/intracytoplasmic sperm injection FET cycles, including 85 cycles with drilling LAH and 86 cycles with thinning LAH, were carried out. The thinning group had a similar ${\beta}$-human chorionic gonadotropin-positive rate (38.4% vs. 29.4%), implantation rate (16.5% vs. 14.4%), clinical pregnancy rate (36.0% vs. 25.9%), miscarriage rate (5.8% vs. 2.4%), ongoing pregnancy rate (30.2% vs. 23.5%), and multiple pregnancy rate (7.0% vs. 10.6%) to the drilling LAH group. There were no significant differences in pregnancy outcomes between subgroups defined based on age (older or younger than 35 years) or ZP thickness (greater or less than $17{\mu}m$) according to the LAH method. Conclusion: The present study demonstrated that partial ZP thinning or drilling resulted in similar outcomes in implantation and pregnancy rates using thawed embryos, irrespective of women's age or ZP thickness.

Uncovering the Antibacterial Potential of a Peptide-Rich Extract of Edible Bird’s Nest against Staphylococcus aureus

Nguyen Thi-Phuong,Duong Tang Van,Le Thai Quang,Nguyen Khoa Thi 한국미생물·생명공학회 2024 Journal of microbiology and biotechnology Vol.34 No.8

The diverse pharmacological properties of edible bird’s nest (EBN) have been elucidated in recent years; however, investigations into its antibacterial effects are still limited. In the present study, we explored the antibacterial activity of a peptide-rich extract of EBN against Staphylococcus aureus, a notorious pathogen. The EBN extract (EEE) was prepared by soaking EBN in 80% ethanol for 2 days at 60°C. Biochemical analyses showed that peptides at the molecular weight range of 1.7-10 kDa were the major biochemical compounds in the EEE. The extract exhibited strong inhibition against S. aureus at a minimum inhibitory concentration (MIC) of 125 μg/ml and a minimum bactericidal concentration (MBC) of 250 μg/ml. This activity could be attributed to the impact of the extract on cell membrane integrity and potential, biofilm formation, and reactive oxidative species (ROS) production. Notably, the expression of biofilm- and ROS-associated genes, including intercellular adhesion A (icaA), icaB, icaC, icaD, and superoxide dismutase A (sodA), were deregulated in S. aureus upon the extract treatment. Our findings indicate a noteworthy pharmacological activity of EBN that could have potential application in the control of S. aureus.