http://stdj.scienceandtechnology.com.vn/index.php/stdj/issue/feed VNUHCM Journal of Science and Technology Development 2023-01-27T22:30:31+00:00 Phuc Van Pham pvphuc@vnuhcm.edu.vn Open Journal Systems http://stdj.scienceandtechnology.com.vn/index.php/stdj/article/view/3984 Establishment of a fiber optic sensor coupled to the plasmonic effect of silver nanoparticles in glucose concentration monitoring 2023-01-27T06:46:26+00:00 http://stdj.scienceandtechnology.com.vn/public/journals/2/article_3984_cover_en_US.png Nguyen Tran Truc Phuong phucpham@sci.edu.vn Vinh Quang Dang phucpham@sci.edu.vn Hanh Kieu Thi Ta phucpham@sci.edu.vn Ngoc Xuan Dat Mai phucpham@sci.edu.vn Anh Tuan Thanh Pham phucpham@sci.edu.vn Dung Van Hoang phucpham@sci.edu.vn Nhu Hoa Thi Tran ttnhoa@hcmus.edu.vn <p><strong>Introduction: </strong>Diabetes is an extremely dangerous disease due to the disorder of glucose metabolism in the body leading to serious complications and the cause other dangerous diseases. Therefore, the continuous monitoring of glucose levels in the body is particularly important in the prevention and treatment of this disease. Optical fiber sensors that apply the LSPR effect of silver nanoparticles show great potential in the field of sensors that enable precise label-free monitoring of analyte concentrations with high sensitivity, which is receiving much attention.</p> <p><strong>Methods: </strong>Based on the sensitivity of the LSPR effect on the surface of AgNPs to the dielectric properties of the medium, namely the refractive index of the analyte solution. Variation in the LSPR conditions of AgNPs leads to either donation or reduction in optical power. Based on that mechanism, the fiber was used as a waveguide and was immobilized on a self-assembled monolayer of AgNPs 1 core surrounded by a microfluidic channel that allows the analyte solution to pass through the sensing area through a biological pump. This process of changing the capacity allows the assessment of glucose concentration in solution to a very small degree of change.</p> <p><strong>Results: </strong>AgNPs of about 90 nm in size were quickly and simply synthesized with high stability and uniformity by chemical reduction with an Ethylene glycol reducing agent as demonstrated by FESEM, and DLS results. The LSPR wavelength of AgNPs solution observed by UV-vis spectrum is 435 nm. At the same time, a fiber-optic sensor system that monitors glucose concentration changes has also been successfully established with a sensitivity of 0.025 RIU corresponding to a detection of limited (LOD) of up to 0.35 mM.</p> <p><strong>Conclusions: </strong>The optical fiber optical sensor based on the LSPR phenomenon of AgNPs was initially established and showed high sensitivity in detecting and monitoring changes in glucose concentration without the use of complex markers or enzymes. The compact size of the fiber sensor opens up the potential for integration into handheld optical devices to help monitor health more proactively.</p> <p><strong>Keywords: </strong>Silver nanoparticles, LSPR, Glucose sensor, optical sensor, detection of limited.</p> 2023-01-20T00:00:00+00:00 ##submission.copyrightStatement## http://stdj.scienceandtechnology.com.vn/index.php/stdj/article/view/3989 Optimization of the optical properties of circular lattice As2Se3 photonic crystal fibers over a wide range of wavelengths 2023-01-27T06:58:20+00:00 http://stdj.scienceandtechnology.com.vn/public/journals/2/article_3989_cover_en_US.png Hoang Trong Duc hoangtrongduc@hueuni.edu.vn Le Tran Bao Tran letranbaotran212@gmail.com Vu Dinh Long dinhlongvv@gmail.com Chu Van Lanh chuvanlanh@vinhuni.edu.vn Nguyen Thi Thuy ntthuy@hueuni.edu.vn <p>In this paper, the dispersion and nonlinear properties of circular lattice photonic crystal fibers with As2Se3 substrates are investigated over a wide wavelength range up to 11 µm. By solving Maxwell's wave equations using the full-vector finite-difference eigenmode method, the optical properties of the PCFs have been analyzed in detail and compared with recent studies. All-normal and anomalous dispersions with small values, very high nonlinear coefficients, and very low confinement losses have been achieved in comparison with the previous publications. The characteristic quantities of the proposed optimal fibers were obtained at the pump wavelength of 2.35 µm including flat dispersion and as small as 1.069 ps/nm.km, non-linear coefficients as high as 62023.377 W<sup>−1</sup>.km<sup>−1</sup>, and confinement losses as low as 10<sup>−21</sup> dB/m, making them suitable for use in a broadband supercontinuum generation process with a low input power. These fibers are suitable low-cost all-fiber laser sources that effectively replace the current glass fibers.</p> 2023-01-20T00:00:00+00:00 ##submission.copyrightStatement## http://stdj.scienceandtechnology.com.vn/index.php/stdj/article/view/3960 Studying the influence of solvent concentration on the fabrication of PCL membrane for wound dressing applications 2023-01-27T07:26:01+00:00 http://stdj.scienceandtechnology.com.vn/public/journals/2/article_3960_cover_en_US.png Khiem Van Nguyen vankhiem1510@gmail.com Nghi Nguyen nghinguyen.295@gmail.com Thanh Ngoc phucpham@sci.edu.vn Tam Phan phucpham@sci.edu.vn Phuc H. Vo phucpham@sci.edu.vn Thao – Nhi Dang Ngoc phucpham@sci.edu.vn Kieu Nguyen phucpham@sci.edu.vn Hiep T Nguyen nthiep@hcmiu.edu.vn <p><strong>Introduction</strong>: The aim of this study is to evaluate the influence of the concentration of acetone (AC) and acetic acid (AA) solvents to fabricate a polycaprolactone (PCL) membrane for wound dressing applications. The viscosity of PCL solutions is evaluated to choose the best AC and AA solvent ratio.</p> <p><strong>Methods</strong>: The PCL membrane was successfully fabricated by the electrospinning method. The physicochemical properties of the membranes were evaluated using a scanning electron microscope (SEM), fiber diameter distribution, water contact angle measurements, the moisture vapor transmission rate, and a biocompatibility assay.</p> <p><strong>Results</strong>: The results show that two samples of 15%PCL-AC and 12%PCL-AC are suitable for fabricating the membrane by electrospinning method.</p> <p><strong>Conclusion</strong>: Therefore, two samples consisting of 12%PCL-AC and 15%PCL-AC with good physical-chemical properties and good biocompatibility can be selected for use in wound dressing applications.</p> 2023-01-20T00:00:00+00:00 ##submission.copyrightStatement## http://stdj.scienceandtechnology.com.vn/index.php/stdj/article/view/3966 Nanosers devices based on Au-studded ZnO nanorod for R6G detection 2023-01-26T23:03:58+00:00 http://stdj.scienceandtechnology.com.vn/public/journals/2/article_3966_cover_en_US.png Khanh Duy Nguyen ndkhanh@hcmus.edu.vn Thu Minh Luong minhthulmt148@gmail.com Khoa Dien Pham phamkhoa847@gmail.com Ngoc Van Le lvngoc@hcmus.edu.vn Thu Thi Hanh Vu vththu@hcmus.edu.vn Hung Vu Tuan Le lvthung@hcmus.edu.vn <p><strong>Introduction</strong>: The prospect of wielding semiconductor–noble metal hybrid nanomaterials as surface-enhanced Raman scattering (SERS) substrates for the ultrasensitive detection of organic molecules in sensing applications has attracted ever-increasing attention. In this study, nanoSERS devices based on Au-studded ZnO nanorods (Au/ZnO) were fabricated using a facile photochemical deposition method for the detection of low-concentration rhodamine 6G (R6G) molecules.</p> <p><strong>Methods</strong>: Analytical techniques such as SEM, EDX, XRD, and UV‒Vis spectroscopy were utilized to investigate the morphology, elemental composition, crystalline structure, and optical absorption of the Au/ZnO nanostructure, respectively. Raman scattering spectroscopy was used to evaluate rhodamine 6G.</p> <p><strong>Results</strong>: The results show that vertically well-aligned ZnO nanorods (NRs) were effectively grown on the seeded glass substrate at 90°C for 4 h, and Au nanoparticles (NPs) with a diameter of approximately 20 nm were successfully deposited onto their surface. Comparing the obtained Au/ZnO substrate to the ZnO NRs and glass substrates, it exhibited superior SERS performance with R6G at a low concentration of 10-3 M. Significantly, it was found that the Au/ZnO for the R6G sensitive limit was approximately 10-9 M. This could be explained due to the surface plasmon resonance (SPR)-induced electromagnetic field enhancement of Au NPs as well as the charge-transfer mechanism between the Au/ZnO substrate and adsorbed R6G molecules under 532 nm laser excitation.</p> <p><strong>Conclusion</strong>: This work demonstrates the potential SERS activity of Au/ZnO substrates, which can identify organic substances at trace levels using the Raman analysis method.</p> 2023-01-20T00:00:00+00:00 ##submission.copyrightStatement## http://stdj.scienceandtechnology.com.vn/index.php/stdj/article/view/3971 Determine three-layer atmospheric electric fields using MGMR3D 2023-01-26T23:21:06+00:00 http://stdj.scienceandtechnology.com.vn/public/journals/2/article_3971_cover_en_US.png Gia Thi Ngoc Trinh ttngia@ctu.edu.vn Phong Thanh Nguyen thanhphong@ctu.edu.vn Si Trung Dang dangtrungsi@cantho.edu.vn Ngọc Thi Kim Nguyen ngocntk.c3taydo@haugiang.edu.vn <p><strong>Introduction</strong>: Measuring atmospheric electric fields is a difficult task because of the volatility of thunderstorms and the lack of control over direct measurement methods such as balloons. MGMR3D is a semi-analytic code that can be used to determine the structures of atmospheric electric fields during thunderstorm conditions indirectly. However, it is required to check whether the MGMR3D results have a good agreement with those provided by the microscopic model, CoREAS, in three-layer electric field cases.</p> <p><strong>Methods</strong>: Using MGMR3D and CoREAS, we compared the intensity and linear and circular polarizations of radio emissions due to extensive air showers given by the two codes.</p> <p><strong>Results</strong>: This work shows that a good agreement was obtained for air showers passing through more complicated electric field structures.</p> <p><strong>Conclusion</strong>: This means that one can use MGMR3D to extract details on the structures of the atmospheric electric fields in thunderclouds.</p> 2023-01-20T00:00:00+00:00 ##submission.copyrightStatement## http://stdj.scienceandtechnology.com.vn/index.php/stdj/article/view/3978 Synthesis and in vitro α-glucosidase inhibitory activity of some of the derivatives of 3-methylrhodanine 2023-01-26T23:34:10+00:00 http://stdj.scienceandtechnology.com.vn/public/journals/2/article_3978_cover_en_US.png Thị Hồng Vân Nguyễn nthongvan1998@gmail.com Thị Thùy Dương Ngô nttduong@hcmus.edu.vn Ngọc Vinh Huỳnh hnvinh@hcmus.edu.vn Thất Quang Tôn ttquang@hcmus.edu.vn Kim Phi Phụng Nguyễn kimphiphung@yahoo.fr Tấn Tài Nguyễn nttai@hcmus.edu.vn <p>In the further research and synthesis of highly bioactive 3-methylrhodanine derivatives, the preparation of benzylidene rhodanines followed by bicyclization to form pyrazole compounds has been undertaken. Using a convenient and simple method, twelve compounds have been synthesized including six benzylidene rhodanine derivatives ranging from a good to excellent yield, with four phenylhydrazone and two pyrazole derivatives at a low yield. The structures of all synthesized compounds were elucidated by spectral methods of analysis. Among them, six heterocyclic compounds, namely 4-(2-phenylhydrazono)-5-benzylidene-3-methylthiazolidine-2-thione <strong>(3'a-3'd)</strong>, 3-(4-nitrophenyl)-2-phenyl-2,6-dihydro-5H-pyrazolo[3,4-d]thiazole-5-thione<strong> (3''e),</strong> and 3-(4-cyanophenyl)-2-phenyl-2,6-dihydro-5H-pyrazolo[3,4-d]thiazole-5-thione<strong> (3''f)</strong> were synthesized for the first time. The synthesized compounds were evaluated in vitro against α-glucosidase and exhibited promising antidiabetic activity with IC<sub>50</sub> values ranging from 11.3 to 21.9 µM.</p> 2023-01-20T00:00:00+00:00 ##submission.copyrightStatement## http://stdj.scienceandtechnology.com.vn/index.php/stdj/article/view/4004 Solvent free, microwave-assisted synthesis and cytotoxicity evaluation of benzoxazole derivatives 2023-01-27T07:10:18+00:00 http://stdj.scienceandtechnology.com.vn/public/journals/2/article_4004_cover_en_US.png Thi Buu Hue Bui btbhue@ctu.edu.vn Thi Diem Suong To tranngocvy.19072010@gmail.com Quang De Tran tqde@ctu.edu.vn <p><strong>Introduction</strong>: This work aims to develop an efficient green synthetic procedure and cytotoxicity evaluation of benzoxazole derivatives, an essential building block in medicinal chemistry research owing to its broad range of pharmacological properties, especially anticancer activity. <strong>Methods</strong>: The microwave-assisted condensation reaction between 2-amino-4-methylphenol and aromatic aldehydes using iodine as the oxidant under solvent-free conditions was explored. The cytotoxicity of the prepared benzoxazoles against the three human cancer cell lines including Lu-1, Hep-G2 and MCF-7 were examined using a MTT assay. Results: Five 2,5-disubstituted benzoxazole derivatives have been successfully synthesized in good yields (67-90%) using iodine as the oxidant under solvent-free microwave irradiation conditions. The initial cytotoxicity evaluation of the four synthesized compounds revealed that compounds <strong>3b</strong> and <strong>3e</strong> exhibited good activity against MCF-7 (IC<sub>50</sub> = 12 μg/mL) and Hep-G2 (IC<sub>50</sub> = 17.9 μg/mL), respectively. Remarkably, compound <strong>3c</strong> showed the best cytotoxicity against MCF-7 at IC<sub>50</sub> = 4 μg/mL. <strong>Conclusion</strong>: Microwave irradiation effectively assisted the condensation reaction between 2-amino-4-methylphenol and aromatic aldehydes in the presence of iodine under solvent-free conditions to facilitate the desired benzoxazoles in good total yields. The prepared benzoxazoles proved to be potent candidates for further study in the development of anticancer agents.</p> 2023-01-20T00:00:00+00:00 ##submission.copyrightStatement## http://stdj.scienceandtechnology.com.vn/index.php/stdj/article/view/3949 Enhancement of the Seebeck Coefficient of C doped SnSe: First Principles Study 2023-01-27T13:31:28+00:00 http://stdj.scienceandtechnology.com.vn/public/journals/2/article_3949_cover_en_US.png Ho Van Binh hvbinh@hcmus.edu.vn Nguyen Huynh Tuan Anh nhtanh@hcmus.edu.vn Do Duc Cuong ddcuong@hcmus.edu.vn <p>The effect of C dopant on the electronic structure and thermoelectric properties of SnSe has been studied using density functional theory (DFT) and by solving the Boltzmann transport equation (BTE). We found that the substitution of C into the Sn site creates a strongly localized defect state with a sharp density for the state peak. This strong modification of band structure reduces the band gap from 0.61 eV to 0.42 eV. It was found that the maximal Seebeck coefficient can be enhanced up to 17.1% and the maximal temperature reduces from 525 K to 280 K. These behaviors can be understood using the Mott equation and Goldsmid – Sharp relation.</p> 2023-01-20T00:00:00+00:00 ##submission.copyrightStatement## http://stdj.scienceandtechnology.com.vn/index.php/stdj/article/view/4000 Studying the inhibition mechanism of human acetyl-CoA carboxylase by aromatic ligands in the treatment of fatty acid metabolic syndrome using computational chemistry methods 2023-01-27T21:55:34+00:00 http://stdj.scienceandtechnology.com.vn/public/journals/2/article_4000_cover_en_US.png Cong Minh Truong Nguyen congminh.ngtruong@gmail.com Truong Xuan Le congminh.ngtruong@gmail.com Thao Xuan Le Thi xuanthao.le@gmail.com Thanh Tho Bui btthanh@hcmus.edu.vn <p><strong>Background</strong>: Metabolic syndrome is a consequence of excess fatty acid accumulation in the human body, causing metabolic disorders related to the role of the two acetyl-CoA carboxylase (ACC) isoforms, ACC1 and ACC2. Inheriting the results from our previous research about "the effective model of human acetyl-CoA carboxylase inhibition by aromatic-structure inhibitors", this research explains the inhibition mechanism of the enzyme by studying the interaction direction, preferential binding sites of aromatic ligands on the isoforms and conformational changes of enzyme-ligand complexes in the body’s environmental conditions (temperature 37 degrees Celsius and water solvent).</p> <p><strong>Methods</strong>: This research applies hard docking combined with molecular dynamics and virtual screening of 14 inhibitory ligand groups, which have 50% enzyme inhibitor (IC<sub>50</sub>) values determined by experiments, including bipiperidylcarboxamide derivatives, polyketides, aryloxyphenoxypropionate, cyclohexanedione, synthetic acyl-CoA fatty acid chains, acylsulfonamide derivatives, Taisho inhibitors, Sanofi-Aventis inhibitors, AstraZeneca inhibitors, Takeda inhibitors, Pfizer inhibitors, Nimbus inhibitors, Amgen inhibitors and Boehringer Ingel-heim inhibitors. The geometric structures of the ligands are modeled and optimized by quantum mechanical methods, including PM3 for ACC1 and DFT at the B3LYP/6-31G(d,p) level for ACC2 based on our previous research about the QSAR enzyme-inhibition models, using Gaussian 09 W software.</p> <p><strong>Results</strong>: Binding energy values at the identified preferential binding sites of aromatic ligands are closely correlated with the experimental log(IC50), which has statistical significance (p &lt; 0.05): R2ACC1 = 96.3% and R2ACC2 = 78.9%. Those sites reveal the five reaction niches on ACC1, involving the two preferential binding regions in the order of amino acids 152 to 643 and 1632 to 2100, and the four reaction niches on ACC2, involving the two preferential binding regions in the order of amino acids 270 to 704 and 1831 to 2299. The molecular dynamic simulation of enzyme-ligand complexes in the body’s environmental conditions confirms that if ligands have fewer stereogenic interactions and are ready to form four types of bonds, including hydrogen, pi-alkyl, pi-cation and alkyl-alkyl bonds, their inhibitory activity will be higher.</p> <p><strong>Conclusion</strong>: The research clarifies the inhibition mechanism of the enzyme in which ligands prefer to interact with amino acids 152 to 643 and 270 to 704 on the biotin carboxylase domain of ACC and amino acids 1632 to 2100 and 1831 to 2299 on the carboxyl transferase domain of ACC. In addition, the fewer stereogenic interactions of ligands and the easier it is to form four types of bonds, including hydrogen, pi-alkyl, pi-cation and alkyl-alkyl bonds, the higher their inhibitory activity.</p> 2023-01-20T00:00:00+00:00 ##submission.copyrightStatement## http://stdj.scienceandtechnology.com.vn/index.php/stdj/article/view/4036 The relationship between autophagy and multidrug resistance in cancer stem cells 2023-01-27T22:30:31+00:00 http://stdj.scienceandtechnology.com.vn/public/journals/2/article_4036_cover_en_US.png Nhan Ngo-The Tran phucpham@sci.edu.vn Khan Dinh Bui phucpham@sci.edu.vn Phuc Van Pham phucpham@sci.edu.vn <p>Cancer stem cells (CSCs) are considered the origin of tumors and cancer. Recently, CSCs have been described as the cause of multidrug resistance (MDR) in almost all cancers. The MDR phenotype of CSCs manifests as the upregulation of ATP-binding cassette subfamily G, isoform 2 protein (ABCG2) in the cell membranes of CSCs. However, recent studies have demonstrated a relationship between MDR and the autophagy process of CSCs. Based on publications indexed in PubMed, Google Scholar, and Scopus, this review summarizes the relationship between autophagy and MDR in CSCs and the approaches to targeting autophagy to reduce MDR in CSCs. Autophagy can be considered a new target to overcome MDR in cancer treatment.</p> 2023-01-27T22:30:30+00:00 ##submission.copyrightStatement##