A new series of 2,3-thiazoline-coumarin hybrid compounds that contained
d
-glucose and
d
-galactose moieties (
4a-g
) were synthesized and their cytotoxic activity was evaluated against breast ...adenocarcinoma (MCF-7), human liver cancer (HepG2), human cervical cancer (HeLa), human melanoma cancer (SK-Mel-2), and human lung cancer (LU-1) cells. To reveal their selectivity toward cancer cells, the compounds were also tested against the human fibroblast cell line MRC-5. The synthesized compounds exhibited potent cytotoxic activity against the tested cell lines with IC
50
values of 1.18-11.32, 1.91-9.81, 1.96-13.16, 1.35-16.12, and 2.12-15.92 μM (against MCF-7, HepG2, HeLa, SK-Mel-2, and LU-1 cells, respectively) compared with Sorafenib, doxorubicin, and 5-fluorouracil. Interestingly, compounds
4a-g
displayed selectivity toward cancer cell lines over MRC-5 (IC
50
3.97-25.75 μM). The most active compounds, including
4d
,
4e
, and
4f
, also displayed potent inhibitory activity against EGFR and HER2 kinases (IC
50
0.15-0.31 and 0.15-0.25 μM, respectively) compared with the standard drug Sorafenib (IC
50
= 0.11 and 0.13 μM, respectively). Molecular docking also showed that the hydrogen binding interactions often occurred between the C&z.dbd;O lactone of the coumarin ring and appropriate amino acid residues, which played a key role in enhancing its potency against both enzymes.
1,3-Thiadiazoline-coumarin hybrid compounds containing
d
-glucose and
d
-galactose moieties have the cytotoxicity against MCF-7, HepG2, HeLa, SK-Mel-2, and LU-1 cells and also EGFR and HER2 kinases. Molecular docking showed key roles in enhancing potency against both enzymes.
Hydroxy derivatives of 4-methyl-2H-chromen-2-one were prepared from hydroquinone and resorcinol through their reaction with ethyl acetoacetate. These hydroxy coumarins were then converted into ...corresponding alkoxy derivatives by reaction with alkyl halides. The yields of 6- and 7-alkoxy-4-methylcoumarins 3a-i and 4a-i were 55−95%. Oxidation of these compounds by selenium dioxide under conventional and microwave-assisted heating conditions produced corresponding 4-formyl compounds 5b-h and 6b-h with yields of 40−67% and 90−93%, respectively. Several 6- and 7-alkoxy-4-methylcoumarins 3a-i, 4a-i and nearly all 6- and 7-alkoxy-4-formylcoumarins 5b-h, 6b-h are novel compounds.
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Access to clean water is still limited in a number of regions, especially country sides, rural, and mountainous areas in Vietnam. Therefore, studies on clean water production by using sustainable and ...affordable processes for locals to access to clean water are of great importance. In this research, we produced laterite-based adsorbents by thermal treatment of natural laterite. The produced adsorbents were characterized in terms of morphology, crystallite, chemical composition, surface functional groups, surface charges, and surface area. The adsorption processes of Ni
2+
and Cu
2+
onto thermally treated laterite were studied. The treated laterite was also deployed to the removal of pollutants from real rain water. Finally, treated laterite was used in a combination system to purify rain water to produce drinking water for households in Hai Dong commune, Hai Hau district, Nam Dinh province. The results showed that the adsorption of Ni
2+
and Cu
2+
by thermally treated laterite reached equilibrium after 40 min and followed the Langmuir sorption isotherm, with the maximum uptake of 27.6 mg/g for Cu
2+
and 17.4 mg/g for Ni
2+
. The second-order-kinetic model described the best the adsorption of Cu
2+
and Ni
2+
from aqueous solution, implying chemisorption was predominant mechanism. The treated laterite was suitable for heavy metal removal but less effective for the removal of anions from water. The combination of solar heating system with treated laterite, sand, and activated carbon allowed to safely produce drinking water from rain water, which presented the water quality respecting the Vietnam national standard for drinking water (QCVN 01:09/BYT).
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Some gluco-conjugated 1H-1,2,3-triazoles possessing 4H-pyrano2,3-dpyrimidines 8a–8s were synthesized via click chemistry between N-propargyl-4H-pyrano2,3-dpyrimidines 6a–6s and peracetylated ...glucopyranosyl azide 7, respectively. This process occurred under catalytic conditions using CuI@montmorillonite as the catalyst in absolute ethanol. The antibacterial, anti-MRSA and antifungal activities of these 1H-1,2,3-triazoles were probed using the minimum inhibitory concentration. Amongst the examined compounds, 1,2,3-triazoles 8g and 8s exhibited good inhibitory activity against the seven tested bacterial strains with MIC values in the range of 0.78–6.25 μg mL−1. They also displayed excellent inhibitory activity against five clinically isolated MRSA strains with MIC values in the range of 0.78–3.125 μM, especially 8g, which exerted excellent activity against all tested MRSA strains and S. aureus with MIC values in the range of 0.78–1.56 μg mL−1. An induced fit docking study was performed to observe the binding efficiency and steric interactions of the lead compound 8g. IFD results showed that compound 8g is compatible with the active site of S. aureus DNA gyrase 2XCS with six hydrogen bonding interactions and two π–π stacking interactions, which suggest that the tested compounds inhibit the synthesis of the S. aureus gyrase enzyme.
Several substituted thiourea derivatives containing 6-carboalkoxybenzothiazole and
d
-glucose moieties 4a–i have been synthesized from the reaction of corresponding alkyl ...2-aminobenzothiazole-6-carboxyl 2a–i with 2,3,4,6-tetra-
O
-acetyl-β-
d
-glucopyranosyl isothiocyanate. Their antimicrobial activity against bacteria (including Gram-positive and Gram-negative) and fungi were screened. The obtained results showed that several compounds exhibited significant inhibition abilities, including 4a, 4b, 4d, 4f, 4i (anti-Gram-positive bacterial), 4a, 4b, 4c, 4d, 4f (anti-Gram-negative bacterial), and 4b, 4d (anti-fungal) with MICs of 0.78–3.125 μg mL
−1
. Thioureas 4b, 4d, and 4i exhibited excellent inhibitory activity against
S. aureus
, in the order of 4d > 4b > 4i, with MICs of 0.78–1.56 μg mL
−1
. These inhibitors also expressed good inhibitory activity against
S. aureus
DNA gyrase and topoisomerase IV enzymes, especially compound 4d, which had IC
50
values of 0.573 and 0.283 μM, respectively, against these tested enzymes. Molecular docking simulations and MM-GBSA calculations indicated that compound 4d interacted effectively with residues, including ALA1068, VAL1071, GLY1072, ASP1073, MET1075, GLY1076, ALA1120, MET1121 (chain B), ASP1088, MET1121, ARG1122 (chain D), DG10, and DC11 (chain E); DG10 and DC11 (chain F), just as the co-crystal interacted at the active site of
S. aureus
DNA gyrase (2XCS).
High-resolution Moho and lithosphere–asthenosphere boundary depth models for Vietnam and its surrounding areas are determined based on a recently released geoid model constructed from surface and ...satellite gravity data (GEOID_LSC_C model) and on 3ʹʹ resolution topography data (mixed SRTM model). A linear density gradient for the crust and a temperature-dependent density for the lithospheric mantle were used to determine the lithospheric structure under the assumption of local isostasy. In a first step, the impact of correcting elevation data from sedimentary basins to estimate Moho depth has been evaluated using CRUST1.0 model. Results obtained from a test area where seismic data are available, which demonstrated that the sedimentary effect should be considered before the inversion process. The geoid height and elevation-corrected sedimentary layer were filtered to remove signals originating below the lithosphere. The resulting Moho and lithosphere–asthenosphere boundary depth models computed at 1ʹ resolution were evaluated against seismic data as well as global and local lithospheric models available in the study region. These comparisons indicate a consistency of our Moho depth estimation with the seismic data within 1.5 km in standard deviation for the whole Vietnam. This new Moho depth model for the study region represents a significant improvement over the global models CRUST1.0 and GEMMA, which have standard deviations of 3.2 and 3.3 km, respectively, when compared to the seismic data. Even if a detailed geological interpretation of the results is out of scope of this paper, a joint analysis of the obtained models with the high-resolution Bouguer gravity anomaly is finally discussed in terms of the main geological patterns of the study region. The high resolution of our Moho and lithosphere–asthenosphere boundary depth models contribute to better constrain the lithospheric structure as well as tectonic and geodynamic processes of this region. The differences in Moho depth visible in the northeast and southwest sides of the Red River Fault Zone confirmed that the Red River Fault Zone may be considered the boundary between two continental blocks: South China and Indochina blocks. However, no remarkable differences in lithosphere–asthenosphere boundary depth were obtained from our results. This suggests that the Red River Fault Zone developed within the crust and remained a crustal fault.
Abstract
The paper focuses on the nonlinear vibration of functionally graded graphene nanoplatelet reinforced composite doubly curved shallow shells resting on elastic foundations. The graphene ...nanoplatelet reinforced composites are assumed to be distributed uniformly and functionally graded through the thickness. The material properties are assumed to be temperature-dependent and are estimated through the Halpin–Tsai micromechanical model, while the Poisson’s ratio, density mass, and thermal expansion are implemented by the rule of mixtures. The mathematical formulation is developed based on the classical shell theory and Von Karman-Donnell geometrical nonlinearity assumption. The dynamical responses of a simply supported functionally graded-graphene nanoplatelet reinforced composite doubly curved shallow shells are obtained by employing the Airy’s stress function and the Galerkin’s method. The responses of nonlinear vibration as time history, frequency-amplitude curve, phase plane graphs, and Poincare maps are carried out in this paper. In addition, the effects of the environment, graphene nanoplatelets weight fraction, graphene nanoplatelets distribution patterns, and thickness-to-length ratio are scrutinized. The obtained results are also compared and validated with those of other studies.
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Background. HCV testing is an important first step for treatment and prevention, particularly for those who are highly vulnerable to HCV infection such as people who inject drugs (PWID). In settings ...where direct-acting antiretroviral medicines are becoming more available, limited information exists about who and where to target to increase the prevalence of HCV testing among PWID. This study is aimed at understanding the prevalence of HCV testing uptake and its determinants of medical services and risk behaviors. Methods. From February 2016 to April 2017, a sample of 509 PWID was interviewed using a structured questionnaire on their history of HCV testing, confirmation, services using in the previous year as well as HCV-related knowledge, and risk behaviors. Multiple logistic regression identified factors associated with ever being tested for HCV before enrollment in the program. Results. Approximately 33% reported ever testing for HCV. Most cited sources of testing are public hospitals and general clinics (68.9%) and outpatient clinics (18.9%). Having ever tested for HCV was positively associated with accessing health services within the prior 12 months (aOR=2.25; 95% CI 1.11-4.58), being currently enrolled in a methadone treatment program (aOR=2.35; 95% CI 1.34-4.08), and/or on ART treatment (aOR=2.30; 95% CI 1.30-4.08). Those who ever delayed in seeking healthcare services for any reason were less likely to get tested for HCV (aOR=0.54; 95% CI 0.35-0.84). Conclusion. HCV testing prevalence is low among PWID in Hanoi despite a very high prevalence of HCV infection. To improve the cascade of HCV testing, it is critical that intervention programs scale up linkages among methadone, outpatient clinics, and HCV services, take steps to reduce stigma and discrimination in both community and, especially, in health care settings, and increase awareness of HCV for PWID by integrating HCV into routine counseling at health care services.
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DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, SIK, UILJ, UKNU, UL, UM, UPUK, VSZLJ
The series of 2-amino-7-propargyloxy-4H-chromene-3-carbonitriles 5a-t were synthesized from corresponding 2-amino-7-phydroxy-4H-chromene-3-carbonitriles 4a-t and propargyl bromide. Two procedures ...were used in these syntheses: K2CO3/acetone and NaH/DMF procedures with yields of 65–89% and 80–96%, respectively. 1H-1,2,3-Triazole-tethered 4H-chromene−d-glucose conjugates 7a-t were synthesized using click chemistry of propargyl ethers 5a-t and tetra-O-acetyl-β-d-glucopyranosyl azide. Cu@MOF-5 was the optimal catalyst for this chemistry. The yields of 1H-1,2,3-triazoles were 80–97.8%. All triazoles 7a-t were evaluated in vitro for anti-microorganism activities. Among tested compounds with MIC values of 1.56–6.25 μM, there were four compounds against B. subtilis, four compounds against S. aureus, and four compounds against S. epidermidis; five compounds against E. coli, four compounds against K. pneumoniae, five compounds against P. aeruginosa, and six compounds against S. typhimurium. Compounds 7c,7d,7f,7h, and 7r had MIC values of 1.56–6.25 μM for three clinical MRSA isolates. Some compounds had inhibitory activities against four fungi, including A. niger, A. flavus, C. albicans, and S. cerevisiae, with MIC values of 1.56–6.25 μM. Some 1H-1,2,3-triazoles had comparatively low toxicity against RAW 264.7 cells.
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•Novel 1H-1,2,3-triazole-tethered 4H-chromene−d-glucose conjugates by click chemistry.•Several triazoles were active for three strains of Gram-(+), four strains of Gram-(−) bacteria (MICs = 1.56–6.25 μM).•Some triazoles had activity against four strains of fungi with MICs of 1.56–6.25 μM.•7c,7d,7f,7h, 7r exerted anti-MRSA activities against all strains with MIC of 1.56–6.25 μM.•1H-1,2,3-Triazoles 7c,7d,7f,7h, 7r had comparatively low cytotoxicity against RAW 264.7 cells.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Some substituted thioureas (
6a-i
) containing a 1,3,4-thiadiazole ring were synthesized by the reaction of the corresponding substituted 2-amino-1,3,4-thiadiazoles
3a-i
with
p
-toluenesulfonyl ...isocyanate in a one-pot procedure. The antibacterial and antifungal activities of these sulfonyl thioureas were estimated using a minimum inhibitory concentration protocol. Almost all the thioureas exhibited remarkable antimicrobial activity. Amongst the studied compounds, thioureas
6a
,
6c
,
6h
, and
6i
were better inhibitors against the bacterium
S. aureus
, with MIC values of 0.78-3.125 μg mL
−1
. These compounds were also tested for their inhibition against
S. aureus
enzymes, including enzymes of DNA gyrase, DNA topoisomerase IV (Topo IV), and dihydrofolate reductase. Amongst the compounds,
6h
was a strong inhibitor, with IC
50
values of 1.22, 53.78, and 0.23, respectively. Induced fit docking calculations were performed to observe the binding efficiency and steric interactions of these compounds. The obtained results showed that compound
6h
was compatible with the active sites of
S. aureus
DNA gyrase
2XCS
. This ligand interacted with residues ASP1083 (chain D), MET1121 (chain B), ARG1122 (chain D), and also with HOH2035, HOH2089, HOH2110, HOH2162. Molecular dynamics simulation in a water solvent system showed that the active interactions with residues ASP083 and MET1121 (chain B), along with ASP1083, MET1121, and ARG1122 (chain D), played an important role in stabilizing complex
6h
/
2XCS
in the active pocket.
Sulfonylthioureas of 2-amino-1,3-thiadiazoles and 4-toluenesulfonyl isocyanate had inhibitions for bacteria, fungi,
S. aureus
DNA gyrase, TopoIV and DHF reductase. IFD, MM-GBSA and MD were performed.
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