VẬT LIỆU TIO2/THAN HOẠT TÍNH TỪ TRO TRẤU VÀ KHẢ NĂNG HẤP PHỤ XANH METHYLENE

In the present work, TiO2/activated-carbon composite (TiO2/RHAC) was synthesized with an assembly method. Activated carbon was fabircated from rice husks. The water-soluble titanium complex was synthesized from anatase via the peroxide complex. The mixture of activated carbon and water-soluble TiO2 was calcined at 600 °C. The obtained samples were characterized by using XRD, SEM, EDX, and UV-Vis-DR. The results show that the obtained composites exhibit excellent adsorption toward methylene blue (MB). The equilibrium data fit the Langmuir isotherm model well. The maximum monolayer capacity calculated from the Langmuir model is 144.7 mg·g–1. The TiO2/RHAC could be self-cleaned after use by photocatalytic degradation. The adsorption capacity insignificantly decreases after three recycles of adsorption, and TiO2/RHAC is a promising adsorbent for removing dyes from the aqueous environment.Trong nghiên cứu này, TiO2/than hoạt tính từ tro trấu (TiO2/RHAC) đã được tổng hợp bằng phương pháp trộn lẫn than hoạt tính và phức titanium. Than hoạt tính được tổng hợp từ tro trấu và phức titanium hòa tan trong nước tổng hợp từ anatase bằng cách tạo phức peroxide. Hỗn hợp được nung trong môi trường thiếu oxy ở 600 °C. Vật liệu tổng hợp được phân tích bằng nhiễu xạ tia X, kính hiển vi điện tử quét và đẳng nhiệt hấp phụ/giải hấp phụ ni tơ. TiO2/RHAC có khả năng hấp phụ cao đối với xanh methylene. Số liệu đẳng nhiệt cân bằng tuân theo mô hình Langmuir và dung lượng hấp phụ cực đại tính theo mô hình này là 144,7 mg·g–1. Chất bị hấp phụ có thể được loại bỏ bằng cách chiếu sáng bằng đèn chiếu nhờ khả năng xúc tác quang hóa của nó. Sau ba lần tái sinh, dung lượng hấp phụ thay đổi không đáng kể. TiO2/RHAC có tiềm năng làm chất hấp phụ xử lý phẩm màu nói chung

THIẾT KẾ, TỔNG HỢP VÀ GIẢI THÍCH HUỲNH QUANG CỦA CHEMODOSIMETER TỪ DẪN XUẤT FLUORESCEIN BẰNG LÝ THUYẾT PHIẾM HÀM MẬT ĐỘ

This work presents the design and synthesis theories of chemodosimeter FS to determine Hg2+ based on lactam ring-opening reaction of fluorescein derivative using density-functional theory (DFT). All theoretical calculations including DFT, TD–DFT, and NBO were carried out with the B3LYP function Gaussian03 software. The comparison of geometric parameters (bond lengths, bond angle, and dihedral angles of atoms) of fluorescein optimized with two basis sets LanL2DZ and 6-311+G(d, p) by means of t–test pairs suggested that LanL2DZ not only reduced the computation time but also gave reliable results. Fluorescent properties of the chemodosimeter FS were explained through TD–DFT and NBO analysis. The results showed that FS was non-fluorescent because of π conjugated system interruption which was due to the existence of the lactam ring. In FG, a product of the reaction between FS and Hg2+, the lactam ring structure was disrupted, and 1,3,4-oxadiazole was formed, resulting in the existence of a conjugated π system from the fluorophore to the receptor, and therefore FG was fluorescent. Accordingly, FS is predicted as an OFF–ON chemodosimeter.Bài báo này, trình bày lý thuyết thiết kế và tổng hợp chemodosimeter FS để xác định Hg2+ dựa vào phản ứng mở vòng lactam của dẫn xuất fluorescein, bằng lý thuyết phiếm hàm mật độ (DFT). Tất cả các tính toán lý thuyết về DFT, TD-DFT, NBO trong bài báo này được thực hiện với hàm B3LYP bằng phần mềm Gaussian03. Đồng thời qua so sánh các thông số hình học (độ dài liên kết, góc liên kết, góc nhị diện của các nguyên tử) của fluorescein đã được tối ưu với hai bộ hàm cơ sở LanL2DZ và 6-311+G(d,p) bằng phương pháp t-test từng cặp, cho thấy có thể sử dụng bộ hàm cơ sở nhỏ LanL2DZ để giảm thời gian tính toán mà vẫn cho kết quả đáng tin cậy. Tính chất huỳnh quang của chemodosimeter FS được giải thích qua phân tích TD-DFT, NBO. Kết quả cho thấy FS không phát huỳnh quang, nguyên nhân là do trong FS tồn tại vòng lactam làm cho hệ liên hợp π trong fluorophore bị gián đoạn dẫn đến sự tắt huỳnh quang trong FS; trong FG ( sản phẩm của FS khi tác dụng với Hg2+) cấu trúc vòng lactam bị phá vỡ, đồng thời tạo vòng 1,3,4-oxadiazole, dẫn tới sự hình thành hệ liên hợp π từ fluorophore cho đến receptor, vì vậy phân tử FG phát huỳnh quang. Do đó, chemodosimeter FS được dự đoán hoặt động kiểu OFF-O

Scavenging of Hydroxyl Radical by Kinsenoside Originated From Anoectochilus Roxburghii: A DFT Approach

- A density functional theory (DFT) study on the hydroxyl radical scavenging properties of Kinsenoside originated from Anoectochilus roxburghii is presented. Two mechanisms, single electron transfer (SET) and hydrogen atom transfer (HAT) are considered. The thermochemical results demonstrate that the SET mechanism is not plausible to occur. With respect to the HAT, the interaction of OH• radical with Kinsenoside is also studied in detail by establishing potential energy surface (PES). This result strongly confirms that the C8H bond decides the radical scavenging activity of Kinsenoside with activation Gibbs free energy (∆G≠) and rate constants (k) of 1.1 kcal/mol and 5.9×10-8 cm3/molecules, respectivel

Bioproduction of prodigiosin from fishery processing waste-shrimp head and evaluation of its potential bioactivities

[[abstract]]The aim of this work was to reuse a fish processing waste, shrimp head powder (SHP), for the production of prodigiosin (PG) via microbial technology and to assess its potential bioactivities. PG was produced in a 12 L-bioreactor system, and the highest PG productivity of 6310 mg L−1 was achieved when Serratia marcescens CC17 was used for fermentation in a novel designed medium (6.75 L) containing 1.5% C/N source (SHP/casein = 9/1), 0.02% K2SO4, ans 0.025% Ca3(PO4)2, with initial pH 7.0, and fermentation was performed at 28 °C for 8 h. The purified PG showed moderate antioxidants, efficient anti-NO (anti-nitric oxide), and acetylcholinesterase (AChE) inhibitory activities. In a docking study, PG showed better binding energy scores (−12.3 kcal/mol) and more interactions (6 linkages) with several prominent amino acids in the biding sites on AChE that were superior to those of Berberine chloride (−10.8 kcal/mol and one linkage). Notably, this is the first investigation using shrimp heads for the mass bioproduction of PG with high productivity, and Ca3(PO4)2 salt was also newly found to significantly enhance PG production by S. marcescens. This study also provided available data on the anti-NO and anti-AChE effects of PG, especially from the docking simulation PG towards AChE that was described for the first time in this study. The above results suggest that SHP is a good material for the cost-effective bioproduction of PG, which is a potential candidate for anti-NO and anti-Alzheimer drugs.[[sponsorship]]科技部[[notice]]補正完

Novel Anti-Acetylcholinesterase Effect of <i>Euonymus laxiflorus</i> Champ. Extracts via Experimental and In Silico Studies

Alzheimer’s disease (AD) is the most common form of dementia, which is recorded as a global health issue. Natural acetylcholinesterase inhibitors (AChEIs) are considered a helpful therapy for the management of symptoms of patients with mild-to-moderate AD. This work aimed to investigate and characterize Euonymus laxiflorus Champ. (ELC) as a natural source of AChEIs compounds via in vitro and virtual studies. The screening parts used, including the leaves, heartwood, and trunk bark of ELC, revealed that the trunk bark extract possessed the highest activity, phenolics and flavonoid content. The in vitro anti-Alzheimer activity of ELC trunk bark was notably reclaimed for the first time with comparable effect (IC50 = 0.332 mg/mL) as that of a commercial AChEI, berberine chloride (IC50 = 0.314 mg/mL). Among various solvents, methanol was the most suitable to extract ELC trunk bark with the highest activity. Twenty-one secondary metabolites (1–21) were identified from ELC trunk bark extract, based on GCMS and UHPLC analyses. Of these, 10 volatile compounds were identified from this herbal extract for the first time. One phenolic (11) and seven flavonoid compounds (15–21) were also newly found in this herbal extract. Of the identified compounds, chlorogenic acid (11), epigallocatechin gallate (12), epicatechin (13), apigetrin (18), and quercetin (20) were major compounds with a significant content of 395.8–2481.5 μg/g of dried extract. According to docking-based simulation, compounds (11–19, and 21) demonstrated more effective inhibitory activity than berberine chloride, with good binding energy (DS values: −12.3 to −14.4 kcal/mol) and acceptable RMSD values (0.77–1.75 Å). In general, these identified compounds processed drug properties and were non-toxic for human use, based on Lipinski’s rule of five and ADMET analyses

Exposure to air pollution and risk of hospitalization for cardiovascular diseases amongst Vietnamese adults: Case-crossover study

Associations between hospital admissions and ambient air pollutants in the Vietnamese population have been reported in previous studies. However, most studies were conducted in Hanoi or Hochiminh city. We used hospital records of seven hospitals in Northern Vietnam to investigate short-term associations between ambient air pollutants and hospital admissions due to cardiovascular conditions.; We used 135'101 hospital records of residents (age ≥15) living in three provinces (Hanoi, Quang Ninh, and Phu Tho) and daily ambient air pollutant concentrations to estimate percentage changes and 95% confidence intervals for hospital admissions due to seven cardiovascular conditions per interquartile range (IQR) increases in daily ambient air pollutants. We used a time-stratified case-crossover analysis adjusting for meteorological factors, indicators of holidays and influenza epidemics. We also investigated modification of effects by age groups (&lt;65 and ≥65), seasons (cold and hot) and hospital levels (national and province level).; Particulate matter concentrations were positively associated with daily hospital admissions due to most cardiovascular conditions. For example, an increment in the two-day average (lag1-2) level of PM; 2.5; by one IQR (34.4 µg/m; 3; ) was associated with a 6.3% (95%CI: 3.0%-9.8%) increase in the daily count of admissions for ischemic heart disease in Hanoi and with 23.2% (95%CI: 11.1%-36.5%) for cardiac failure in Quang Ninh. Moreover, hospitalisations for stroke in Hanoi and cardiac failure in Phu Tho showed strong positive associations with SO; 2; . The findings also show that estimates varied by age groups, seasons and hospital levels.; Ambient air pollutants were associated with daily cardiovascular admissions in Northern Vietnam. The findings underline the important role of ambient air pollutants as a trigger of cardiovascular conditions

An Ab Initio RRKM-Based Master Equation Study for Kinetics of OH-Initiated Oxidation of 2-Methyltetrahydrofuran and Its Implications in Kinetic Modeling

Cyclic ethers (CEs) can be promising future biofuel candidates. Most CEs possess physico-chemical and combustion indicators comparable to conventional fuels, making them suitable for internal combustion engines. This work computationally investigates the kinetic behaviors of hydrogen abstraction from 2-methyl tetrahydrofuran (2MTHF), one of the promising CEs, by hydroxyl radicals under combustion and atmospheric relevant conditions. The various reaction pathways were explored using the CCSD(T)/cc-pVTZ//M06-2X/aug-cc-pVTZ level of theory. The Rice–Ramsperger–Kassel–Marcus-based master equation (RRKM-ME) rate model, including treatments for hindered internal rotation and tunneling, was employed to describe time-dependent species profiles and pressure and temperature-dependent rate coefficients. Our kinetic model revealed that the H-abstraction proceeds via an addition-elimination mechanism forming reaction complexes at both the entrance and exit channels. Eight different reaction channels yielding five radical products were located. The reaction exhibited complex kinetics yielding a U-shaped Arrhenius behavior. An unusual occurrence of negative temperature dependence was observed at low temperatures, owing to the negative barrier height for the hydrogen abstraction reaction from the C-H bond at the vicinity of the O-atom. A shift in the reaction mechanism was observed with the dominance of the abstraction at Cα-H of 2MTHF ring (causing negative-T dependence) and at CH3 (positive-T dependence) at low and high temperatures, respectively. Interestingly, the pressure effect was observed at low temperatures, revealing the kinetic significance of the pre-reaction complex. Under atmospheric pressure, our theoretical rate coefficients showed excellent agreement with the available literature data. Our model nicely captured the negative temperature-dependent behaviors at low temperatures. Our predicted global rate coefficients can be expressed as k (T, 760 Torr) = 3.55 × 101 × T−4.72 × exp [−340.0 K/T] + 8.21 × 10−23 × T3.49 × exp [918.8 K/T] (cm3/molecule/s). Our work provides a detailed kinetic picture of the OH-initiated oxidation kinetics of 2MTHF. Hence, this information is useful for building a kinetic me chanism for methylated cyclic ethers

On the Inhibitability of Natural Products Isolated from Tetradium ruticarpum towards Tyrosine Phosphatase 1B (PTP1B) and α-Glucosidase (3W37): An In Vitro and In Silico Study

Folk experiences suggest natural products in Tetradium ruticarpum can be effective inhibitors towards diabetes-related enzymes. The compounds were experimentally isolated, structurally elucidated, and tested in vitro for their inhibition effects on tyrosine phosphatase 1B (PTP1B) and α-glucosidase (3W37). Density functional theory and molecular docking techniques were utilized as computational methods to predict the stability of the ligands and simulate interaction between the studied inhibitory agents and the targeted proteins. Structural elucidation identifies two natural products: 2-heptyl-1-methylquinolin-4-one (1) and 3-[4-(4-methylhydroxy-2-butenyloxy)-phenyl]-2-propenol (2). In vitro study shows that the compounds (1 and 2) possess high potentiality for the inhibition of PTP1B (IC50 values of 24.3 ± 0.8, and 47.7 ± 1.1 μM) and α-glucosidase (IC50 values of 92.1 ± 0.8, and 167.4 ± 0.4 μM). DS values and the number of interactions obtained from docking simulation highly correlate with the experimental results yielded. Furthermore, in-depth analyses of the structure–activity relationship suggest significant contributions of amino acids Arg254 and Arg676 to the conformational distortion of PTP1B and 3W37 structures overall, thus leading to the deterioration of their enzymatic activity observed in assay-based experiments. This study encourages further investigations either to develop appropriate alternatives for diabetes treatment or to verify the role of amino acids Arg254 and Arg676

Combinatory in silico investigation for potential inhibitors from Curcuma sahuynhensis Škorničk. & N.S. Lý volatile phytoconstituents against influenza A hemagglutinin, SARS-CoV-2 main protease, and Omicron-variant spike protein

Curcuma sahuynhensis Škorničk. & N.S. Lý has been discovered recently whose antiviral potential is unknown, thus deserved for discovery-phase screening. A combination of experimental characterization, quantum calculation, molecular docking simulation, physicochemical analysis, and absorption, distribution, metabolism, excretion, and toxicity (ADMET) was designed for the theoretical argument on the potentiality of oil-based components (1−27) against H5 hemagglutinin in influenza A virus (PDB-5E32), wild-variant SARS-CoV-2 main protease (PDB-6LU7), and SARS-CoV-2 Omicron spike protein (PDB-7T9J). Theoretical arguments based on various computational platforms specify the most promising bio-inhibitors, i.e. 23 (bio-compatibility: ground energy −966.73 a.u., dipole moment 3.708 Debye; bio-inhibitability: DS̅\bar{{\rm{DS}}} −12.5 kcal mol−1; drug-likeness: mass 304.7 amu, log P 1.31; polar-interactability: polarizability 32.8 Å3) and 26 (bio-compatibility: ground energy −1393.66109 a.u., dipole moment 5.087 Debye; bio-inhibitability: DS̅\bar{{\rm{DS}}} −11.9 kcal mol−1; drug-likeness: mass 437.5 amu, log P 4.28; polar-interactability: polarizability 45.7 Å3). The pkCSM-ADMET model confirms their favorable pharmacokinetics and pharmacology. The total essence is unsuitable for use as an antiviral source in its pure form since the most bioactive candidates are accountable for the small content. Particularly, 23 (7β-hydroxydehydroepiandrosterone) and 26 (ethyl cholate) are recommended for further experimental efforts of isolation and bioassaying trials