bluuebunny/crossref_metadata_2025 huggingface dataset:
Sulfanilic acid catalysed one‐pot three‐component Mannich reaction for synthesis of β‐amino ketones
Authors: Kulkarni Pramod
Published: March 2024

We have reported sulfanilic acid as an exceedingly competent catalyst for one‐pot Mannich reaction to give β‐amino carbonyl compounds in good to excellent yield within a short reaction time. The various organic acids have screened; like gallic acid, 4‐hydroxy benzoic acid, 4‐amino benzoic acid, phenylacetic acid, chloroacetic acid, sulfosalicylic acid, sulfanilic acid, chloro benzoic acid, phthalic acid, salicylic acid, cinnamic acid, hippuric acid, 1‐naphthyl acetic acid, o‐amino benzoic acid, p‐TSA, succinic acid, malic acid, and among them sulfanilic acid is a suitable catalyst. The reaction condition was optimized with respect to the solvent, the amount of catalyst as well as the variation of the ketone, aldehyde, and amine substrates. The procedure is mild, effective, ecofriendly, and the use of the minimum amount of catalyst.
Fluorescent properties of some polythiophenes synthesized from 2‐(thiophen‐3‐yl)acetohydrazide and acetophenone
Authors: Linh Nguyen Ngoc , Hung Ha Manh , Oanh Doan Thi Yen , Linh Bui Thi Thuy , Cong Nguyen Tien , Chinh Nguyen Thuy , Hoang Thai , Trung Vu Quoc
Published: March 2024

In this study, new polythiophenes containing hydrazone groups from derivatives of acetophenone were synthesized by chemical oxidative coupling polymerization. Ultraviolet‐visible spectroscopy (UV‐Vis) combined with infrared (IR) analyses proved the supposed structure of novel polythiophenes and proved conformance of the expected synthetic method. Morphology and surface properties of the synthesized polymers were investigated by field‐emission scanning electron microscopy (FE‐SEM). Thermal gravimetry analysis (TGA) has been reported that there was still the presence of small FeCl3 catalyst in polymers and polymers had a stable thermal stability under air atmosphere. The polymers displayed fluorescence emissions at about 590 nm attributed to the π‐conjugated polythiophene. Polymers without doping have a good electrical conductivity (around 4.03×10–7 S/cm at 1 MHz).
Phytochemical investigation of Eurycoma longifolia roots collected in Gia Lai province, Viet Nam
Authors: Ha Vo Khanh , Hanh Truong Thi Minh , Nam Pham Cam , Lien Giang Thi Kim , Chi Mai Thi Phuong , Thao Tran Thi Phuong
Published: March 2024

From the roots of Eurycoma longifolia, seven compounds including β‐carboline‐2N‐oxide‐1‐propionic acid (1), 9,10‐dimethoxycanthin‐6‐one (2), β‐carboline‐1‐propionic acid (3), infractine (4), eurylene (5), eurycomanone (6), 14,15‐β‐hydroxyklaineanol (7) were isolated. Their structures were determined by means of spectroscopic methods (UV, IR, HR‐ESIMS, 1D and 2D NMR). Compound (1) has been isolated for the first time from nature and compound (4) has been isolated for the first time from Eurycoma longifolia.
Heat treatment for bactericidal particulate silver plating on 316L stainless steel
Authors: Ly Pham Thi , Van Tuan Nguyen , Anh Nguyen Tuan , Thuy Dao Bich , Ha Pham Thi , Cuong Ly Quoc , Quan Vo An
Published: March 2024

The paper presents the impact of heat treatment on the characteristics of the particulate silver plating on 316L stainless steel. Heat treatment was applied in Argon gas media at 500, 600, and 800 oC for 15 minutes. Advanced evaluation methods was applied as scanning electron microscopy (SEM) for surface morphology assessment, tape tests for adhesion determination of silver plating, atomic absorption spectroscopy (AAS) for released concentration of ions in the simulated body fluid (SBF). The antibacterial effect of the silver plating versus Escherichia coli was evaluated through inhibition of bacterial growth after 60 minutes of exposure. The SEM images indicated that there is no change on the grain boundaries after heat treatment. The adhesion of the silver plating increased while increasing temperature from 500 to 800 oC; and the released concentration of silver ion in SBF decreased. The antibacterial effect efficiency of silver plating was from 92 to 99 %. The released concentration of silver ion in SBF after 168 hours was in range of 0.012÷0.18337 μg/mL with average silver plating content was 6.0 mg, much lower in comparison with the allowed threshold of released concentration of silver ion in human body fluid (10 μg/mL).
Electrically conductive membrane based on epoxidized natural rubber‐graft‐polyaniline nanomatrix
Authors: Ha Nguyen Thu , Hieu Vu Huy , Nam Nguyen Hai , Nghia Phan Trung , Ougizawa Toshiaki , Kawahara Seiichi
Published: March 2024

In this study, electrically conductive membrane based on natural rubber was prepared through graft‐copolymerization of aniline on natural rubber, and epoxidation in latex stage. The structural characterization of the resulting material through NMR spectroscopy confirmed that polyaniline and epoxy group were successfully introduced to natural rubber chain. The polyaniline nanomatrix formed in materials was confirmed through TEM observation. The thermal properties, mechanical properties, electrical conductivity of the resulting material, i.e., epoxidized deproteinized natural rubber‐grafted‐polyaniline (EDPNR‐g‐PAni), were investigated in comparison with those of raw natural rubber. The obtained results indicated that tensile strength and thermal resistance of EDPNR‐g‐PAni were higher than that of the raw material. The electrical conductivity of EDPNR‐g‐PAni was 6.86 × 10‐4 S/cm, which was remarkably improved. This result was attributed to the synergistic effect of polyaniline nanomatrix and epoxy group in natural rubber.
Cytotoxic constituents from the stem barks of Ceriops decandra (Griff.) W. Theob.
Authors: Linh Kieu Thi Phuong , Binh Pham Thanh , Van Chien Nguyen , Trung Nguyen Quoc , Thong Vu Huy , Van Thanh Nguyen , Thao Nguyen Phuong
Published: March 2024

A phytochemical survey aiming to acquire pharmacologically active substances has resulted in the isolation of five dolabrane‐ (1–5), and ent‐pimarane‐type diterpenoids (6) were isolated from the methanol extract of C. decandra (Griff.) W. Theob. stem barks, via various chromatographic separations. Their structures were elucidated to be ent‐5α,3,15‐dioxodolabr‐1,4(18)‐diene‐2,16‐diol (1), tagalene I (2), ent‐5α,2,15‐dioxodolabr‐3‐ene‐3,16‐diol (3), tagalsin S (4), notolutesin H (5), and ent‐8,15R‐epoxypimaran‐16‐ol (6) by comprehensive analysis of spectroscopic data (1D, 2D NMR, and ESI‐MS data) as well as comparison with the previous literature. All of the isolates were evaluated for their cytotoxicity against human lung cancer (SK‐LU‐1), human hepatocellular carcinoma (HepG2), and human breast cancer (MCF‐7) cell lines. Compounds 2 and 6 exerted inhibitions toward three tumor cell lines (SK‐LU‐1, HepG2, and MCF‐7) with IC50 values between 5.63 and 11.70 μg/mL, while other compounds exhibited weak to moderate or no cytotoxic activities (IC50 > 20 μg/mL).
Synthesis of 1,1’‐diphenyl‐2‐thienyl‐2’‐(4‐substituted‐styryl)ethenes via oxidative Heck coupling reaction and photophysical studies
Authors: Thanh Le Tin , Hai Dang Xuan , Hien Nguyen , Hai Le Thi Hong , Thanh Le Thanh , Tung Dang Thanh
Published: March 2024

In this paper, we report the synthesis of four new 1,1’‐diphenyl‐2‐thienyl‐2’‐(4‐substituted‐styryl) ethenes via one‐step oxidative Heck coupling reaction of 1,1’‐diphenyl‐2,2’‐dithienylethene (DPDTE). This is a useful method to alkenylate DPDTE in order to enhance its fluorescence as well as its aggregation‐induced emission (AIE) properties. 1,1’‐Diphenyl‐2‐thienyl‐2’‐(4‐methylstyryl)ethene showed low fluorescent intensity in CHCl3 solution but very high AIE intensities. On the other hand, 1,1’‐diphenyl‐2‐thienyl‐2’‐(4‐acetoxystyryl)ethene showed both high fluorescence in CHCl3 solution and AIE intensities.
Low‐lying states of TaGe−/0/+ clusters from the CASPT2 and DMRG‐CASPT2 calculations
Authors: Van Tan Tran , Tri Tran Quoc , Thao Nguyen Minh , Mai Tran Thi Xuan , Hanh Nguyen Thi Hong
Published: March 2024

The low‐lying states of TaGe−/0/+ clusters have been investigated with the CASPT2 and DMRG‐CASPT2 methods. The DMRG‐CASPT2 method with an active space of 20 orbitals is expected to provide highly accurate relative energies of the electronic states. The leading configurations, bond distances, bond orders, vibrational frequencies, atomic charges, and relative energies of the electronic states are reported. The ground states of TaGe−/0/+ clusters are respectively predicted as the 3Δ, 4Φ, and 5Δ. The atomic charges of Ta in these ground states are more positive than those of the Ge atom. The electron detachment energies of the anionic and neutral clusters are estimated to be 1.62 and 6.84 eV. The Franck‐Condon factor simulations for the detachments of one electron from the anionic and neutral clusters exhibit extensively vibrational progressions because of the large structural difference between the initial and the final state.
Froth flotation process and its application
Authors: Mondal Sangita , Acharjee Animesh , Mandal Ujjwal , Saha Bidyut
Published: March 2024

The paper is about the froth flotation process and its application. It is a metallurgical process for the extraction of metals in a pure state from their ores: especially for sulfide ores. Froth flotation is one of the steps which is generally performed before roasting and it deals with the surface chemistry of liquids and of the minerals to be separated. This process requires a particular setup to be performed which contains different components. Surfactants play the most important role here. Different types of surfactants are used in different ways and each of them plays a crucial role like, collectors, frothers, froth stabilizers, depressants and activators, pH regulators etc. The sulfide ore flotation process can be studied by both chemical and electrochemical phenomena considering the interfacial energies. A broad application of this process in industrial field is the flotation of iron ores which is of two types: direct and reverse flotation. The later one is again based on two different types as cationic and anionic reverse flotation. In all these processes different types of flotation reagents are used. Another application is separation of malachite and azurite ore using sulfidization flotation.
Electrochemical determination of acetaminophen in pharmaceutical formulations and human urine using Ag‐Au bimetallic nanoparticles modified electrode
Authors: Phuong Ton Nu My , Diem Phan Nu Ha , Toan Tran Thanh Tam , Phong Nguyen Hai , Lieu Pham Khac , Son Le Van Thanh , Hoa Tran Thai , Khieu Dinh Quang
Published: March 2024

In the present paper, the Ag‐Au bimetallic nanoparticles (Ag‐AuNPs) was prepared by the simultaneous reduction of silver and gold with dextran solution. A novel glassy carbon electrode (GCE) modified by Ag‐AuNPs was employed for the voltammetric determination of acetaminophen (ACT). The nanoparticles were characterized by UV‐visible spectroscopy method which confirmed the homogeneous formation of the bimetallic alloy nanoparticles. Transmission electron microscopy (TEM) revealed that the synthesized bimetallic nanoparticles’ size was in the range of 20‐50 nm. The electrochemical behavior of ACT at the Ag‐AuNPs/GCE exhibited a higher electrocatalytic effect compared to that observed when GCE was modified with each constituent of the composite and bare GCE. A linear relationship between anodic current of ACT concentration was obtained over the range of 0.4 to 10.2 μM with a detection limit of 0.54 μM. The proposed method was simple, less time consuming and showed a high sensitivity. The application of this electrode to determine ACT in tablets and urine samples was proposed. The application of this electrode to determine ACT in tablets and urine samples was proposed. The results analyzed by the proposed method was not significantly different from that analyzed by standard HPLC method.
Spectroscopic (FTIR and UV), quantum Chemical, antifungal and antioxidant investigations of (E)‐7‐(4‐(trifluoromethyl)benzylidene)‐1,2,6,7‐tetrahydro‐8H‐indeno[5,4‐b]furan‐8‐one: A combined experimental and theoretical study
Authors: Adole Vishnu Ashok , More Rahul Ashokrao , Shinde Rahul Ashok , Dhonnar Sunil Laxman , Jagdale Bapu Sonu , Shinde Sachin Girdhar , Patil Arun Vitthal , Pawar Thansing Bhavsing
Published: March 2024

In the current study, we report the antifungal, antioxidant, and computational study of (E)‐7‐(4‐(trifluoromethyl)benzylidene)‐1,2,6,7‐tetrahydro‐8H‐indeno[5,4‐b]furan‐8‐one (FMBIF). The structure of the FMBIF was confirmed using spectroscopic techniques such as UV‐Vis, FT‐IR, 1H NMR, 13C NMR, and HRMS. Antifungal activity of the FMBIF was evaluated against four fungal strains namely Rhizopus oryzae, Mucor mucido, Aspergillus niger, and Candida albicans. The FMBIF was found to exhibit a good spectrum of antifungal activity against all the tested fungal strains. Additionally, it was also revealed to show good antioxidant potential. The Gaussian‐03 package was used to perform the density functional theory (DFT) calculations. The structural, chemical, UV‐Vis, and vibrational characteristics were evaluated using the DFT/B3LYP approach with a 6‐311++G(d,p) basis set. Using optimized molecular structure, the absorption wavelength, excitation energy, force strength, and electronic transitions were calculated using the TD‐DFT method with the CAM‐B3LYP functional and 6‐311++G(d,p) basis set. Mulliken atomic charges and molecular electrostatic potential surfaces are explored to investigate the electron density distribution in the titled compound. The DFT investigation's spectroscopic results were in good concurrence with experimental data.
Mg2+ embedded MIL‐101(Cr)‐NH2 framework for improved CO2 adsorption and CO2/N2 selectivity
Authors: Ky Vo The , Quang Duong Tuan
Published: March 2024

The development of a CO2‐selective adsorbent with high CO2 uptake capacity and CO2/N2 selectivity is a challenge. In this work, Mg2+‐embedded MIL‐101(Cr)‐NH2 frameworks (Mg@MCrN) were simply prepared via a facile one‐step synthesis. The results indicated that the incorporation of a proper amount of Mg2+ into the host MIL‐101(Cr)‐NH2 increased the porosity of the resultant adsorbent. Noticeably, the temperature‐programmed desorption of CO2 (TPD‐CO2) analysis revealed that the prepared Mg@MCrN contained new metal active sites along with coordinately unsaturated Cr(III) sites and amine (NH2) sites of the framework. At 100 kPa and 25 oC, the prepared Mg@MCrN‐0.2 exhibited the highest CO2 uptake capacity and CO2/N2 selectivity of ca. ~3.04 mmol.g‐1 and ca. ~ 60, respectively, surpassing the parent MOF and many other CO2 benchmark adsorbents. Moreover, the CO2 adsorption capacity over the Mg2+‐incorporated MIL‐101(Cr)‐NH2 remained even after 5 cycles of adsorption‐desorption under pressure swing from 0 to 100 kPa. This work opens a new perspective for developing efficient CO2‐selective materials.
Effects of bioactive substances to prolong the shelf‐life and inhibit the formation of black spots in black tiger shrimp (Penaeus monodon) preserved at 0 degree C
Authors: Tam Le Nhat , Anh Huynh Nguyen Que , Khue Doan Nhu , Uyen Phan Thuy Xuan , Thanh Nguyen Ba , Huong Nguyen Thi , Thien Van Hong , Van Hai Chu , Vu Truong Huynh Anh , Hung Nguyen Quoc
Published: March 2024

The objective of this study was to extend the shelf‐life and inhibit the process of black spots formation in giant black tiger shrimp (Penaeus monodon) by using 1.5 % solutions of the bioactives including: gallic acid, caffelic acid and cinnamaldehyde. Shrimp samples were dipped in the solutions for ten minutes, at 4°C and stored at 0°C for 15 days. Total viable count (TVC), melanosis evaluation method, chemical quality indexes including total volatile base nitrogen (TVB‐N), trimethylamine nitrogen (TMA‐N), pH and hypoxanthine values were used to evaluate the effectiveness of the treatments. TVC values, melanosis score of shrimp samples treated with bioactive compounds appeared more slowly, TVB‐N and TMA‐N values changed exponentially, hypoxanthine values increased linearly with storage time, and pH decreased on day 2, then increased gradually. Shelf life of treated samples were found to be longer than that of the control sample (8 days), and had a better ability to inhibit melanosis, in particular, the samples treated with a solution of cinnamaldehyde had the longest shelf life of 14 days, compared with 13 days of samples treated with caffelic acid and 12 days of the ones treated with gallic acid.
Synthesis of two indomethacin‐dimers with biological activity on heart failure
Authors: Lauro Figueroa‐Valverde , Francissco Diaz‐cedillo , Marcela Rosas‐Nexticapa , Maria López‐Ramos , Virginia Mateu‐Armad Maria , Magdalena Alvarez‐Ramirez , Tomas Lopez‐Gutierrez , Alejandra Garcimarrero‐Espino
Published: March 2024

There are few studies for the preparation of dimers with biological activity. In this research, two indomethacin dimers were prepared from indomethacin and characterized by NMR spectroscopic methods. Then, biological activity produced by indomethacin dimers were evaluated on heart failure using a biological model. The results indicate that protocols used for synthesis of indomethacin dimers do not require special conditions to give a good yielding. Other data showed that indomethacin dimers decrease heart failure. In conclusion, indomethacin dimers would be good candidates for treating of heart failure.
Survey on different polyphenol extraction methods from avocado seed (Persea americana Mill) and assay on their antioxidant and acute toxicity activities
Authors: Hue Ha Thi , Thai Nguyen Minh , Dao Phan Thi Anh
Published: March 2024

A comprehensive investigation of extraction methods on the efficiency of the total polyphenol contents (TPC) and antioxidant activities for both avocado seed groups with and without removing antinutrients (signed as groups A and B) and assessing acute toxicity on the extraction products. The Soxhlet extraction showed the most effective method for producing an avocado seed extract possessing the highest TPC and strong antioxidant activities, followed by the maceration, hot extraction, and percolation extraction. Interestingly, it was found that antinutrients containing in the seed can reduce TPC. For instances, sample 4B (Soxhlet method) exhibited the largest TPC (189.67±3.58 mgGAE/g DW) and DPPH inhibitory activity (IC50 = 19.24±1.23 μg/mL), while those of the sample 2A (percolation method) were 68.95±3.79 mgGAE/g DW and 67.48±0.98 μg/mL, respectively. Additionally, sample 4B did not exhibit acute oral toxicity (Dmax = 21.05 g/kg mice weight), indicating a safe and high antioxidant activity of avocado seed extract for clinical applications. A high correlation analyzed by Pearson's correlation was found for the TPC to DPPH assay and ferric reducing/ antioxidant assay, showing their correlation parameters of ‐0.898 and 0.847 (p < 0.05), respectively.
Spectroscopic (UV and fluorescence), biological, DFT and molecular docking studies of 3,5‐diethyl‐2r,6c‐di(4‐fluorophenyl)piperidin‐4‐one picrate
Authors: Savithiri S. , Bharanidharan S.
Published: March 2024

The spectroscopic investigations of 3,5‐diethyl‐2r,6c‐di(4‐fluorophenyl)piperidin‐4‐one picrate (3,5‐DEDFPP) are evaluated by UV–Vis and fluorescence techniques. At the B3LYP/6‐311++G(d,p) level of theory, the DFT approach was utilized to optimize the molecular structure. The dipole moment, polarizability, and hyperpolarizability values are calculated at same level of theory. NBO analysis was used to calculate the hyperconjugative interaction energy (E(2)) and electron densities of donor (i) and acceptor (j) bonds. The molecule's energy gap was discovered using HOMO and LUMO calculation. The Mulliken atomic charges of the carbon, nitrogen and oxygen atoms were calculated and using at the same level. The thermodynamic properties of the title compound were calculated at different temperatures in gas phase. The 3,5‐DEDFPP's bacterial activity was evaluated against Escherichia coli, Staphylococcus aureus, Bacillus subtilis, Vibreo cholerae, and Pseudomonas aeruginosa, as well as fungal strains such as Candida albicans, Aspergillus niger, Aspergillus flavus, and Trichophyton rubrum. The interaction of the title compound to bind to a target protein was studied using molecular docking analysis.
Spectroscopic analysis, DFT studies and molecular docking of 2,3‐dichloro‐benzylidine‐(2‐trifluoromethyl‐phenol)‐amine
Authors: Mohammed Ameen K. K. , Hajam Towseef Ahmad , Syed Ali Padusha M. , Saleem H. , Sarathi D. Partha
Published: March 2024

2,3‐dichloro‐benzylidine‐(2‐trifluoromethyl‐phenol)‐amine (2DBTP) has been synthesized and characterized by various spectroscopic techniques including FT‐IR, FT‐Raman, UV‐Vis and 1H, 13C NMR spectroscopy. The equilibrium geometry and harmonic vibrational frequencies were investigated by density functional theory (DFT) at B3LYP/6‐311++G(d,p) basis set. The vibrational wavenumber assignments were made on the basis of total energy distribution (TED) calculations using Veda 4 program. The harmonic wavenumbers calculated at DFT were in line with the experimental values. The non‐linear optical properties (NLO) were calculated. Stability of the molecule arises from hyperconjugative interactions and charge delocalization was analyzed by natural bond orbital (NBO) analysis. Molecular electrostatic potential (MEP), mulliken atomic charges were also calculated. The energy gap of the molecule was found by HOMO and LUMO calculation. TD‐DFT calculations have been carried out on the optimized geometry to further understand the electronic transitions in the UV‐Vis spectrum of the compound. In addition, the 1H and 13C NMR chemical shift values of 2DBTP in the ground state were also calculated using Gauge invariant atomic orbital (GIAO) method. The molecular docking solved the binding mode of 2XCT complex with the ligand. The investigated molecule revealed the inhibition activity of the ligand against anti‐bacterial protein topoisomerase DNA gyrase enzyme (PDB ID: 2XCT).
Fabrication of ultra‐thin alumina membranes utilizing waste aluminum cans
Authors: Anh Dang Hoang , Toan Ngo Quoc , Tung Pham Cao Thanh , Son Cu Thanh , Nguyen Hieu Pham Trung , Nguyen Hoang‐Duy
Published: March 2024

We report on utilizing waste aluminum cans for anodic aluminum oxide (AAO) membranes fabrication. Aluminum (Al) presents in the cans is about 97 % tested via inductively coupled plasma‐mass spectrometry. Synthesis process of the AAO membranes includes heat‐treatment and surface polishing of the waste Al sheets, first anodization, aluminum oxide layer removing, second anodization, aluminum substrate separating and pore‐widening. Thickness and morphology of the prepared AAO membranes are observed through a field emission scanning electron microscopy. By controlling the second anodization time, the AAO membranes possess ultra‐thin thickness in the range of ~60‐650 nm. The average pore densities ~1.2 × 1010 and ~ 3.0 × 1010 hole/cm2 of the AAO membranes are obtained at constant anodization voltage of 40 and 25 V, respectively. Hole diameter of the AAO membranes can be varied from 30 to 95 nm via managing the pore‐widening time. The ultra‐thin AAO membranes with order nano‐hole arrays can be used as hard‐templates which are promising for unique nanostructures synthesis at low cost and environment friendly.
A facile synthesis, characterization and docking studies of 2‐methyl‐3‐(5‐phenyl‐4H‐(1,2,4)triazol‐3‐yl)‐quinoxaline and its derivatives
Authors: Reddy S. Ramakrishna , Reddy G. Ganga , Reddy Ch. Venkata Ramana , Reddy B. Srinivasa , Laxminarayana E.
Published: March 2024

A new series of 2‐Methyl‐3‐(5‐phenyl‐4H‐(1,2,4)triazol‐3‐yl)‐quinoxaline derivatives have been synthesized by simple and efficient method by using 3‐methyl‐quinoxaline‐2‐carboxylic acid, 3‐methyl‐quinoxaline‐2‐carboxylicacidethylester and 3‐methyl‐quinoxaline‐2‐carboxylichydrazide as reaction intermediates in good yields. All the synthesized compounds were characterized by spectral and elemental analysis. The molecular docking studies of 2‐Methyl‐3‐(5‐phenyl‐4H‐(1,2,4)triazol‐3‐yl)‐quinoxalinecarried to predict the anti bacterial potential.
The influence of technological conditions and molecular weight of PEG on basal spacing of Vietnamese bentonite
Authors: Thuy Nguyen Thi , Duc Vu Minh
Published: March 2024

The unique expansion properties of the interlayer space of montmorillonites allow for surface modification of bentonite. PEG is a nonionic polymer that can adsorb and intercalate into the interlayers of bentonite. The results of FTIR and TGA spectra allow confirming that PEG has not only covered bentonite but also inserted into the interlayers of bentonite. Therefore, the modified product can be applied not only as a dispersant in polymer composites, but also as an adsorbent. Moreover, a variety of technological factors affecting modification have been studied and the most suitable conditions have been proposed. In which, temperature, stirring speed, time and suspension concentration were selected at 25°C, 800 rpm, 8 h and 2 wt.%, respectively. The influence of the component ratio (Ben/PEG) on the modification process was also studied. The most suitable Ben/PEG ratio for each PEG type was also given. The results show that the interlayer spacing in modified bentonite depends not only on the technological conditions, the composition ratio but also on the molecular weight of PEG. Thus, the choice of PEG for bentonite modification will determine the d001 basal spacing of modified product.
Flavonoids as potential agents for development of multi‐target drugs for covid‐19 treatment: An in silico study
Authors: Hang Nguyen Thu , Van Phuong Nguyen
Published: March 2024

COVID‐19 is an infectious disease caused by SARS‐CoV‐2 that is spreading in many countries around the world. In attempts to discover compounds that have an effect on SARS‐CoV‐2, many important molecular targets have been identified, involved in viral infection and replication including spike protein, main protease, capthesin L, helicase, 2‐O‐methyltransferase, endoRNAse. In this study, we would like to identify pot ential flavonoids that could simultaneously inhibit 3CLP, capthesin L, endoRNAse, 2‐O‐methyltransferase, and PLP from a 4389‐flavonoid database using molecular docking, molecular dynamics simulation, pharmacokinetic and toxicity prediction. Out of 4389 compounds, 79 potential flavonoids that could simultaneously inhibit five COVID‐19 molecular targets were identified. Pharmacokinetic and toxicity prediction showed that these compounds were well absorbed from the gastrointestinal tract and safe for human use. These potential compounds were noteworthy during drug research and development for SARS‐CoV‐2 treatment.
Synthesis and cytotoxicity of nitrogen‐containing curcuminoids against cancer cell lines
Authors: Van Pham Thi Bich , Huy Nguyen Trong , Hao Hoang Minh
Published: March 2024

In a previous study, we performed the structural modification of the curcumin skeleton by varying substituents in phenyl rings. In continuation of that work, we now focus on the synthesis of nitrogen‐containing curcuminoids by a pyrazole cyclization between the free β‐diketone curcuminoids bearing ‐OCH3/‐OH/‐F substituents in aromatic rings and phenyl hydrazine hydrochloride. Seven N‐phenyl pyrazole curcuminoids (1a‐7a) were synthesized in yields of 39‐73 % and derivative (7a) was reported for the first time. Synthesized compounds were evaluated for their cytotoxicities against HepG2, LU‐1 and KB cancer cell lines. Compared to the pristine compound, i.e., curcumin, compound (1a) demonstrated better inhibitory activities toward three cell lines. Derivative (2a) exhibited higher anti‐cancer capacity against HepG2 and LU‐1 than curcumin. Analogues (4a‐7a) bearing pyrazole ring and ‐OCH3/‐F groups in aromatic rings displayed low/inactive anti‐cancer activities. In addition, compared to pyrazole curcumin (PC), derivative (1a) containing N‐phenyl substituent displayed lower cytotoxicities toward HepG2 and KB cell lines.
An in silico study on inhibitability of Baloxavir marboxil, Baricitinib, Galidesivir, Nitazoxanide, and Oseltamivir against SARS‐CoV‐2
Authors: Bui Thanh Q. , Hai Nguyen Thi Thanh , My Tran Thi Ai , Phong Nguyen Ho Vu , Nhan Ngu Truong , Quy Phan Tu , Nguyen Nguyen Phuong Dai , Nhung Nguyen Thi Ai
Published: March 2024

Baloxavir marboxil (D1), Baricitinib (D2), Galidesivir (D3), Nitazoxanide (D4), and Oseltamivir (D5) are well‐known performing broad‐spectrum activity against a variety of viruses, thus holding high potentiality towards SARS‐CoV‐2. Quantum properties were examined using density functional theory (DFT). The inhibitability of the drugs towards Angiotensin‐converting enzyme 2 (ACE2) and SARS‐CoV‐2 main protease (6LU7) was evaluated by molecular docking simulation, while their bio‐compatibility was justified by physicochemical properties obtained from QSARIS‐based analysis in reference to Lipinski's rule of five. Quantum analysis suggests that the compounds are highly favourable for intermolecular interaction towards protein structures. Given ligand‐ACE2 systems, the inhibitory effectiveness follows the order D3‐ACE2 > D4‐ACE2 > D2‐ACE2 > D5‐ACE2 > D1‐ACE2; and the corresponding order for ligand‐6LU7 systems is D2‐6LU7 > D4‐6LU7 > D3‐6LU7 > D5‐6LU7 > D1‐6LU7. Galidesivir is predicted as the most effective inhibitor towards both targeted protein structures (DSaverage ‐13.1 kcal.mol‐1) and the most bio‐compatible molecule (Mass 264.9 amu; LogP ‐0.9; Polarisability 26.8 Å3). The theoretical screening suggests all drugs, especially Galidesivir (D3), promising for treatment of SARS‐CoV‐2 infection and encourages in‐related clinical trials.
Quantum mechanical studies of 5‐amino‐2‐(6‐(2‐hydroxyethyl)‐3‐oxononyl) cyclohex‐2‐enone isolated from a marine algae
Authors: Begum Sk. Rameeza , Rao D. Jagadeeswara , Rao K. V. Raghava , Ramakrishna Y. , Elangovan N. , Thomas Renjith
Published: March 2024

The compound C1 from marine algae was isolated and characterized by FTIR, FT‐Raman and UV‐Vis, with compared to experimental and simulated methods. The compound optimized with DFT method with the WB97XD and 6‐311 + G(2d,p) basis set level. The infrared and Raman spectrum were calculated with same basis set level; the simulated spectrum good agreement with experimental one. The HOMO‐LUMO and MEP also calculated with above mentioned same basis set level; this study is mainly predicted to the biological activity of the titled compound C1. The wave function studies like localized orbital locator, electron localized function, average localized ionization energy and non‐covalent interaction also studied for another theoretical evidence of the titled compound. The ADMET properties are also studied for in this compound for the support of Swiss ADMET online tool. Molecular docking study showed a high binding affinity of ‐7.9 kcal/mol to act as a 5‐hydroxytryptamine release stimulant.
Synthesis and study of superparamagnetic Fe3O4/C core‐shells nanoparticles for Cd2+ adsorption
Authors: Dang Le Hai , Van Hai Nguyen , Huyen Nguyen Thi Ngoc , Doanh Vu Viet , Thu Le Dieu , Hoang Tran Vinh
Published: March 2024

In this study, Fe3O4/C core‐shell (Fe3O4/C‐EG) nanocomposite adsorbent was synthesized to treat wastewater contaminated with Cd2+ ions. The structural properties of the material have been determined using X‐ Ray diffraction, fourier transform infrared (FT‐IR). The morphology of the sample was assessed by transmission electron microscopy (TEM) and the images show that Fe3O4/C‐EG nanoparticles with an average particle size of 15‐20 nm are encased by a carbon shell. The specific surface area of Fe3O4/C‐EG measured by the BET method is 64.78 m2/g. The adsorption isotherm and kinetics were investigated, and the equilibrium data were fitted well to the Langmuir model with a maximum adsorption capacity of 35.85 μmol/g. Results also show that the material was a favorable adsorbent for Cd2+ ions.
Inhibitory, biocompatible, and pharmacological potentiality of dammarenolic‐acid derivatives towards α‐glucosidase (3W37) and tyrosine phosphatase 1B (PTP1B)
Authors: Quy Phan Tu , Van Hue Nguyen , Bui Thanh Q. , Triet Nguyen Thanh , Van Chen Tran , Van Long Nguyen , Smirnova Irina , Petrova Anatasia , Thao Tran Thi Phuong , Ninh Pham Thi , Ha Nguyen Thi Thu , Nhung Nguyen Thi Ai
Published: March 2024

Dammarenolic‐acid derivatives experimentally demonstrated possessing inhibition activity towards α‐glucosidase might be used as the evidence to retrieve an inhibitory mechanism and subjected for computational screening on other diabetes‐related proteins, e.g. tyrosine phosphatase 1B. Seven structures reported in our preceding work (denoted as 1‐7) were subjected for an in silico investigation in this study on inhibitability towards protein structure PDB‐3W37 by molecular docking simulation. The computer‐based results see a good agreement with those from laboratory‐based reports, with the order of static stability: 3‐3W37 > 1‐3W37 > 7‐3W37 > 2‐3W37 > 6‐3W37 ~ 5‐3W37 ~ 4‐3W37 (negligible activity). Together, experiment‐theory reveals the most promising candidates are 1‐3 and 7. The in‐theory order for most promising inhibitors regarding protein structure UniProt‐PTP1B is: 1‐PTP1B > 6‐PTP1B > 4‐PTP1B. Quantity‐structure relationship analyses (i.e. QSARIS and ADMET) expect 1‐3 as compounds with sufficient bio‐ and pharma‐compatibility. Altogether, the results specify 1 as the most promising candidate for multi‐purpose inhibition towards diabetes‐based proteins, thus encouraging elevated efforts for validation and further development for application.
Synthesis of adsorption‐photocatalysis bifunctional Ag3PO4/SBA‐15 for degradation of Rhodamine B
Authors: Mo Nguyen Thi , Thanh Pham Tien , Cam Le Minh
Published: March 2024

In present work, Ag3PO4/SBA‐15 was prepared for the degradation of rhodamine B dye (RhB). The synthesized material was characterized by XRD, FTIR, FESEM, ultraviolet‐visible diffuse reflectance spectroscopy, and photoluminescence spectrometry. The obtained results indicate that Ag3PO4/SBA‐15 inherits both the adsorption ability of SBA‐15 and photocatalytic activity of Ag3PO4, therefore, exhibits high efficiency in the degradation of RhB. The kinetics of the process was also studied. The optimum reaction time was determined to be 60 minutes. The process of dye degradation is 3/2‐order with respect to rhodamine B. The material shows high ability to be recovered with the relatively high photocatalytic stability.
Chemical constituents and cytotoxicity of Lepidotrigona ventralis propolis
Authors: Thanh Le Nguyen , Thu Nguyen Anh , Oanh Vu Thi Kim , Hue Vu Thi , Minh Nguyen Tu , Minh Nguyen Phan Ngoc , Xuan Truong Vinh , Phuong Diep Thi Lan , Lien Nguyen Thi Phuong
Published: March 2024

From propolis of Lepidotrigona ventralis stingless bee collected in Tuyen Quang province, eight compounds were isolated and determined as lantanolic acid (1), moronic acid (2), (+)‐eudesmin (3), (+)‐yangambin (4), (+)‐syringaresinol (5), (+)‐pinoresinol (6), dihydroconiferyl alcohol (7) and vanillin (8) using NMR and MS spectral data. Compounds 1 and 2 showed significant cytotoxicity against HepG‐2 cancer cell line with IC50 values of 25.84±0.48 and 39.92±1.14 μg/mL, respectively.
Modification of ZnO nanoparticles as an efficient activator for rubber vulcanization
Authors: Thuong Nghiem Thi , Tu Pham Ho Anh , Hung Dang Viet , Ha Cao Hong , Long Nguyen Han
Published: March 2024

In the present work, ZnO nanoparticles (NPs) was modified with stearic acid (SA) to form ZnO‐SA and subsequently used as an activator for natural rubber vulcanization. Modified ZnO NPs were characterized by FTIR, X‐ray diffraction, SEM, and contact angle measurement. ZnO‐SA NPs were used in the vulcanization of natural rubber (NR) and compared with unmodified ZnO NPs. It was found that ZnO‐SA NPs decreased scorch time and activation energy of the vulcanization process compared to unmodified ZnO NPs. Mechanical performances of NR vulcanized with ZnO‐SA NPs and ZnO NPs were characterized by tensile properties, hardness shore A, compression set, permanent set, and rebound resilience. ZnO‐SA NPs not only increased the vulcanization process of NR but also improved the mechanical properties. This was interpreted as an increment in crosslinking density and better compatibility of ZnO‐SA NPs with NR.
Phytochemistry of the unpolar extract of Carica papaya leaves and its antidengue activity
Authors: Thao Tran Thi Phuong , Dung Nguyen Thi , Ninh Pham Thi , Van Chien Tran , Anh Ho Ngoc , Hau Vu Thi Bich , Thuy Nguyen Thi Thu
Published: March 2024

Antidenge activity of the n‐hexane, ethyl acetate and n‐butanol extracts from the leaves of Carica papaya against four dengue virus serotypes (DENV1‐4) were evaluated. As a result, the n‐hexane extract showed the best antiviral activity on all denge virus with PNRT50 from 15.625 to 31.25 μg/ml. From n‐hexane extract, nine compounds including cycloartenol (1), cycloart‐23,25‐dien‐3β‐ol (2), cycloart‐25‐ene‐3β,24β‐diol (3), cycloart‐25‐ene‐3β,24α‐diol (4), 25‐hydroxycycloart‐23‐ene‐3‐one (5), β‐sitosterol (6), stigmasterol (7), nonacosan‐1‐ol (8), all‐trans‐polyprenol‐12 (9) were isolated. Structural elucidation of the above compounds was supported by analysis of their spectral data. Compounds 2‐5, 8 and 9 were isolated for the first time from the plant Carica papaya.
Electrospun PVA/α‐mangostin nanofibers, their anti‐bacterial ability and anti‐oxidation performances
Authors: Dung Hoang Tran , Van Huy Nguyen , Dung Ngo Thanh , Tung Doan Thanh , Yen Nguyen Thi , Thanh Ngo Ba , Hien Nguyen Thi , Hoang Thai , Lu Le Trong , Chinh Nguyen Thuy
Published: March 2024

α‐mangostin which has been extracted from mangosteen peel is known as an excellent bioactive substance with high anti‐oxidation, anti‐bacterial, anti‐inflammatory, etc. The application of α‐mangostin in the biomedicine field is potential and promising. However, the α‐mangostin has a poorly solubility in aqueous. Using polymers as carriers to improve the solubility of α‐mangostin has been attracted in research. In this work, poly(vinyl alcohol) (PVA) crosslinked with citric acid has been used as a carrier to enhance the solubility of α‐mangostin. The PVA/α‐mangostin nanofibers were prepared by electrospinning method with the ratio of PVA/α‐mangostin varied 100/0, 100/1 and 100/3 (w/w). The obtained PVA/α‐mangostin nanofibers have smooth and homogenous surface. The introduction of α‐mangostin into PVA can increase mechanical properties of PVA. The slight shift in wavenumbers characterized for stretching vibration of hydroxyl groups in the PVA/α‐mangostin nanofibers as compared to PVA nanofibers suggested that hydroxyl groups in PVA can interact with hydroxyl groups in α‐mangostin. The solubility of α‐mangostin in ethanol/pH buffer solutions was enhanced significantly in the presence of PVA. The antibacterial and anti‐oxidation ability of PVA/α‐mangostin nanofibers was increased as increasing α‐mangostin concentration. These results showed that the nanofibers are potential for application in biomedicine field as a wound dressing material or in food industry.
Influence of the black seed oil modified epoxy resin/biscycloaliphatic epoxide monomer weight ratio on thermal properties of photocrosslinked coatings
Authors: Dung Nguyen Tien , Hien Le Xuan , Thanh Do Minh
Published: March 2024

The influence of the black seed oil modified epoxy resin (EBSO)/monomer 3,4‐epoxycyclohexylmethyl 3,4‐epoxycyclohexane carboxylate (BCDE) weight ratio in the coatings based on the compounds and photoinitiator triarylsulfonium hexafluoroantimonate (TAS) on thermal properties of photocrosslinked coatings have been studied. The chemical structure of investigated UV‐cured coatings was characterized by IR spectrometric analysis. Their thermogravimetric (TG) and differential scanning calorimetry (DSC) behavior were determined by TG and DSC analysis, respectively. It was shown that the testing atmosphere had almost no effect to the form of TG, DTG curves and little effect on value of weight degradation of investigated coatings. The volatilization of low molecular weight compounds was observed in the range from room temperature to 360oC while the thermal degradation of the coatings occurred in the range from 360 to 455.5oC. The augmentation of the EBSO/BCDE weight ratio from 20/80 to 80/20 led to an increase of the degradation temperatures in the nitrogen atmosphere; extreme character of weight loss variation as well as the reduction of glass transition temperatures of the coatings from 79.8oC (Tg1) and 83oC (Tg2) to 36.8 (Tg1) and 38.9oC (Tg2), correspondingly.
Adsorption of proteinogenic amino acid on Al‐ and C‐doped boron nitride nanotube (BNNT)
Authors: Mohammadi Mohsen Doust , Abdullah Hewa Y. , Louis Hitler , Qadir Karwan W. , Ikenyirimba Onyinye J.
Published: March 2024

Efficient determination of proteinogenic amino acid is of great relevance, and evaluating the intrinsic interaction of this amino acid of interest with nanotubes play a crucial role in adsorption and sensing mechanism, and in determining proteinogenic amino acid measurement index. As such, the study apparently sought to examine the adsorption of the proteinogenic amino acid (proline) on the bare surfaces of carbon boron nitride, boron nitride, and boron nitride doped with the aluminum element nanotubes. In accordant with the geometric optimization, different dispersion models: PBE0, ωB97XD, M06‐2X, and B3LYP‐D3(GD3BJ) were used; note that the latter is used only in wave function analysis studies. Studies show that the strongest adsorption belongs to boron nitride nanotubes doped with aluminum (BNAldopNT), with similar and more negative adsorption energy of ‐0.719, ‐1.393, ‐1.001, and ‐1.098eV respectively for the various benchmarked functionals utilized in the study. Then the highest energy and adsorption strength was obtained for the boron nitride nanotube (BNNT), and at the end is the carbon boron nitride nanotube (i.e. BNAldopNT > BNNT > BC2NNT). As such, in tandem with the energetic analysis carried out suggests that BNAldopNT might be a potent and preferred candidate for the adsorption of the proteinogenic amino acid (proline molecule)among other studied nanotubes, with respect to their respective adsorption energy values
Preparation and antimicrobial properties of polymer blend based on LLDPE and polyhexamethylene guanidine
Authors: Hanh Le Thi My , Van Cuong Bui , Minh Vu Xuan , Lan Pham Thi , Dung Nguyen Tuan , Lam Tran Dai
Published: March 2024

Antibacterial packaging represents an active packaging solution crafted to uphold the quality and safety of products. One of the popular polymer used in food packaging is Linear Low‐Density Polyethylene (LLDPE), due to its low cost, ease of processing, and high mechanical properties. Polymer blend based on LLDPE and antibacterial agent PHMG were prepared in the presence of PE‐g_AM compatibilizer and DCP initiator. The inclusion of PHMG resulted in a decline in the material's tensile strength. Specifically, in the sample containing 2% PHMG content, the tensile strength decreased by 11.6% in comparison to the original PE; whereas the elongation at break of the samples slightly increased. IR analysis confirmed the presence of characteristic groups of PHMG after the reaction. The polymer blend material acquired demonstrated antibacterial effects against both Gram‐negative (E. coli) and Gram‐positive (S. aureus) bacteria owing to the existence of PHMG within the material. The polymer blend sample LLDPE/2%PHMG/0.2%DCP/5%PE‐g_AM demonstrated the best antibacterial effect. The diameter of the S. aureus resistant zone reached 1.9 cm, 2.4 times bigger than the those of E. coli. The obtained properties of mechanical properties and antibacterial ability, polymer blend based on LLDPE/PHMG is suitable for application of antibacterial packaging film.
An investigating on the structures of Sc2Ge6− cluster and its CO adsorption by quantum chemical calculation
Authors: Thao Nguyen Minh , Thanh Bui Tho , Cang Phan Trung , Hoang Ly Huy , Linh Ho Sy , Van Thang Bui , Lieu Dang Thi Thu , Xuan Pham Minh , Huong Nguyen Thi Lan , Tram Nguyen Thi Ngoc
Published: March 2024

The structures of the Sc2Ge6− cluster and its CO adsorption have been computational investigated. The density functional theory and couple cluster calculation are used to gether with the genetic algorithm in determine the minimum structures. This global minimum structure has the shape of a tetragonal bipyramid having two Sc atoms at two tops of pyramids binding with one edge of Ge‐Ge. The ground electronic state of the global minimum isomer is the 2B2 state in the C2v symmetry. The most stable isomer of Sc2Ge6− has been used to study the CO adsorption. The calculated results indicate that the Sc2Ge6− cluster has a good interaction with the CO molecule. The adsorption positions are around the Sc atom with two stable models include adsorbing the C atom and adsorbing both the C and O atoms of the CO molecule. Scandium doped germanium cluster can be used to produce materials that can treat CO gas by adsorption method.
Atomic‐level insights into single Pt atom catalysts on CeO2 support
Authors: Thang Ho Viet , Hy Duong The , Anh Phan The , Xuan Nguyen Thi Minh
Published: March 2024

Precious Pt metals deposited on reducible CeO2 oxide have been widely used in exhaust gas treatment. However, the high cost of Pt metals is the main barrier that prevents from applying the Pt metals. Therefore, a lot of efforts have been dedicated to reducing the Pt size as small as possible, aiming at maximizing Pt metal utilization efficiency. The smallest ultimate size that Pt metal can be deposited on CeO2 as single atom structures. Furthermore, the supported single Pt atom catalysts enhance catalytic performance and selectivity compared to Pt cluster or Pt particle counterparts. However, the electronic structures of single Pt atom catalysts at the atomic level are a challenge for the experimentalist, leading to a lack of important information in using these catalysts. Here, we aim to figure out the nature of the high thermal stability of single Pt atom catalysts on CeO2 support using density theory functional and compared to experimental data from previous studies. This study will provide useful information on single Pt atom catalysts on CeO2 support aiming at boosting synthesis and applications applying CeO2‐supported Pt.
Potential wMUS81 inhibitory activity of triterpenoids isolated from Helicteres hirsuta and Pterospermum truncatolobatum: A molecular docking studies
Authors: Linh Le Thi Khanh , Long Pham Quoc , Minh Pham Thi Hong , Hoa Le Thi Phuong , Quan Pham Minh , Quang Dang Ngoc
Published: March 2024

The winged‐helix domain within the N‐terminus of human MUS81 has been considered as potential target for drug development since the inhibition of this protein might significantly enhance the sensitivity of various cancer cells towards anticancer drugs. Nine cytotoxic triterpenoids previously purified from Helicteres hirsuta and Pterospermum truncatolobatum were selected for the docking experiment. All these synthesized triterpenoids were docked with wMUS81 model to shed light on the mechanism of action of bioactive compounds within the active site of the targeted protein. Obtained results indicated that compounds 3β‐O‐trans‐caffeoylbetulinic acid (4) and betulonic acid (5) might be considered as specific inhibitor of this protein based on their high binding affinity and interacting residues analysis.