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In this study, we use a time-varying parameter vector autoregression in conjunction with the extended joint connectedness approach (TVPVAR-EJC) to examine the interrelationships among five variables, namely digitalization measured by the number of individuals using the Internet (% of the population), mobile cellular subscriptions (per 100 people), human capital index, CO2 emissions, and GDP, from 1996 to 2019 in Vietnam. Net total directional connectedness of digitalization and other variables suggests that it consistently acts as a net shock transmitter, whereas human capital was found to be a net receiver of corresponding shocks from 1997 to 2019. The emission of CO2 was a net critical receiver in 1998 but remained as a net transmitter for the rest of the period. Pairwise connectedness reveals that digitalization appeared as a net shock transmitter in connection with the human capital index and GDP. In the relationship with human capital, digitalization's role was critical. [ABSTRACT FROM AUTHOR]

Complex shear modulus imaging (CSMI) is a technique used to determine the elasticity and viscosity of soft tissues; it aids in investigating tissue structure and detecting tumors. CSMI methods can be categorized into quasi-static and dynamic approaches. The dynamic method utilizes force excitation and particle velocity measurements to estimate the Complex Shear Modulus (CSM). However, noise poses a challenge to shear wave estimation, affecting accuracy. Researchers are actively exploring adaptive filtering techniques and signal processing algorithms to address the noise issue and obtain reliable shear wave estimations. By integrating the Algebraic Helmholtz Inversion (AHI) method and the Least Mean Square (LMS) filter, imaging accuracy can be enhanced by mitigating the impact of noise. This study introduces a pioneering advancement in Complex Shear Modulus Imaging (CSMI). A new approach is proposed, using a dual-frequency excitation technique, strategically employing 100 Hz and 150 Hz frequencies. The proposed method is meticulously designed to enhance the overall efficiency of CSMI. Furthermore, a highly effective signal sampling and spectrum estimation procedure is introduced, aimed at elevating the accuracy of Algebraic Helmholtz Inversion (AHI) and significantly mitigating computational complexity in contrast to prior investigations. [ABSTRACT FROM AUTHOR]

Evaluation of the arsenic content in food has always been an important issue due to its high toxicity. This is especially relevant for Vietnam, a country with high arsenic contamination. The present study focuses on the development of a model function to predict As uptake in the vegetable Brassica perviridis as a function of the conditions of plant growth and soil parameters. The content of the As and Fe in the samples was determined by neutron activation analysis at the IBR-2 reactor; the soil pH and total organic carbon content were measured in the Institute of Nuclear Science and Technology –Vietnam Atomic Energy Institute (Hanoi, Vietnam). Obtained data have shown that As uptake in the Brassica perviridis plants grown in northern Vietnam could be presented as a function of soil parameters such as pH, organic carbon content, and Fe content, but is not dependent on As content in soil. Particularly high Fe content in Vietnamese soils contribute to As immobilization and prevent its uptake by plants. Regression Data Analysis was used to extract the model function with good corresponding statistics: correlation factor R > 0.97, the probability p-value of independent variable coefficients in the range from 1.86E-07 to 0.007, and the significance F of the model < 1.49E-11. The obtained values demonstrate the reliability and the trueness of the applied model at given soil characteristics and conditions of plants cultivation. The concertation of As in irrigating water could be regarded as the main source of the As uptake in plants and need to be investigated. [ABSTRACT FROM AUTHOR]

Adsorption of dichlorodiphenyltrichloroethane (DDT) on titanium dioxide supported on graphitic carbon nitride (TiO2/cGN) was investigated using a novel, accurate and broadly parametrized self-consistent tight-binding quantum chemical (GFN2-xTB) method. The adsorption energy, charges on atoms, bond orders and reaction pathway have been determined and analyzed to figure out the nature of the adsorption process. The obtained results indicate that the adsorption of DDT on the pristine cGN is physical of nature. The combination of TiO2 and cGN significantly enhanced the material's adsorption performance. DDT is chemically adsorbed on TiO2/cGN due to the formation of chemical bonds between atoms of DDT and TiO2/cGN. In addition, the adsorption process does not involve a transition state. [ABSTRACT FROM AUTHOR]

A series of substituted 4H-pyrano[2,3-d]pyrimidines were synthesized from corresponding substituted 4H-pyrans by ring-closing reaction with acetic anhydride or acetic acid in the presence of trifluoroacetic acid as catalyst. The successive alkylation reaction of lactam N–H bond on pyrimidine-4-one ring was carried out using propargylic bromide in dry acetonitrile in the presence of anhydrous potassium carbonate. Three procedures applied for this purpose, including MW-assisted heating conditions at power of 100 W, under conventional heating conditions in water bath at 50 °C, and under ultrasound-assisted heating conditions at 50 °C. Dry acetonitrile was used as reaction solvent. Excellent yields of N-propargyl-4H-pyrano[2,3-d]pyrimidine derivatives were obtained. The single-crystal X-ray structure of compound 6a has been recorded, and the study helps to confirm the structure of synthesized N-propargyl derivative of 4H-pyrano[2,3-d]pyrimidines 6a–6p. [ABSTRACT FROM AUTHOR]

The Northeastern coastal zone of Vietnam possesses high biodiversity and rich ecosystems like coral reefs, seagrasses, beaches and mangroves. It also includes the Ha Long Bay Natural Heritage site (UNESCO 1994) and the Cat Ba Biosphere Reserve (MAB/UNESCO 2004) as well as hosts the Economic Development Triangle (Hai Phong−Ha Noi–Quang Ninh) established by the Government of Vietnam. As one of the coastal ecosystems, sandy beach ecosystems attracted more attention during recent decades because of their essential role for human welfare and in environmental protection. A few studies concentrated on sustainable management of sandy beach based on environmental and ecological protection and enhance the beach quality for recreational use. The DPSIR (Driving force Pressure State Impact Response) framework describes the logical interaction among systems and finds out the cause and consequence of social-economic development activities to the environment and resources. In this study, the DPSIR was applied on the sandy beaches in the Northeastern coast of Vietnam to reveal the main environmental problems on sandy beaches including the decline of the natural landscape around the beaches and the degradation of the environment. It also pointed out that tourism development in association with urbanization and sea reclamation is the main driving forces for environmental degradation of the sandy beaches. Therefore, local authorities of Hai Phong and Quang Ninh should take into account several main responses to policies on inter-province coordination and managerial measures with a wider scope, which integrate socio-economic and physical factors, proximity, accessibility, and neighborhood to manage healthy coastal ecosystems and sandy beaches in particular. An integrated coastal management program for the Northeastern coast of Vietnam needs to be developed and carried out to follow the laws of Vietnam as well as to meet local urgent requirements. [ABSTRACT FROM AUTHOR]

Searching for bioactive agents from medicinal plants, eleven constituents were isolated from Polyscias guilfoylei stem for the first time, including a nucleoside uracil (1), two sterols β-sitosterol (2) and daucosterol (3), a saponin androseptoside A (4), two lignans (+)-pinoresinol (5) and (+)-syringaresinol (6), four phenolic acids protocatechuic acid (7), methyl protocatechuate (8), caffeic acid (9), and 5-O-caffeoylquinic acid (10), and a flavonoid quercitrin (11). Metabolites 1, 4, and 6–11 have never been observed in genus Polyscias before. Phenolic compounds 7 and 9 possessed the respective IC50 values of 21.33 and 13.88 µg/mL in DPPH (2,2-diphenyl-1-picrylhydrazyl) antioxidative assay, as compared with that of the positive control resveratrol (IC50 = 13.21 µg/mL). From density functional theory (DFT) calculated approach, the DPPH free radical scavenging capacity of two compounds 7 and 9 can be explained by the role of OH groups at carbons C-3 and C-4. Antioxidative actions of these two potential agents are followed HAT (H atom transfer) mechanism by OH bond disruption in gas, but SPLET (sequential proton loss electron transfer) mechanism in solvents water and methanol. Compared to 4-OH group, 3-OH group showed better bond disruption enthalpies and better kinetic energies since it reacted with HOO• and DPPH radicals. Sterols 2–3 and flavonoid 11 induced the IC50 values of < 2.0 µg/mL better than the positive control acarbose (IC50 = 184.0 µg/mL) in α-glucosidase inhibitory assay. Their interactions with human intestinal C- and N-terminal domains of α-glucosidase were explored using molecular docking study. The obtained results proved that compounds 2, 3, and 11 bind relatively stronger with the C-terminal domain than to the N-terminal domain through pivotal residues in the binding site and could be hypothesized as mixed inhibitors. [ABSTRACT FROM AUTHOR]

Phytochemical investigation of the ethyl acetate extract of Styrax annamensis leaves has led to the isolation and determination of a new lignan, 7R,8S,7′S,8′R-3,4,3′-trimethoxy-9,4′,7′-trihydroxy-8.8′,7.O.9′-lignan (1), together with a known compound, 4-ketopinoresinol (2). Compound 2 was isolated from the genus Styrax for the first time, and showed moderate activity to capture the DPPH radical with the IC50 value of 56.74 ± 0.79 μg/mL. [ABSTRACT FROM AUTHOR]

Purpose: In this study, we focused on the role of elevated serum interleukin 6 (IL-6) concentration in predicting 5-year cardiovascular mortality in hemodialysis patients using low-flux dialyzer reuse. Materials and methods: We measured serum IL-6 concentrations in 236 hemodialysis patients (138 males and 98 females) to predict 5-year cardiovascular mortality. We assessed the baseline demographics of all patients who had a mean age of 44 years and a median hemodialysis duration of 38.5 months. We divided all patients into two equal groups based on the serum IL-6 concentration: G1 (n = 118) with serum IL-6 concentration < 6.78 pg/L and G2 (n = 118) with serum IL-6 concentration ≥ 6.78 pg/L. Results: After the 5-year follow-up, 45 patients died due to cardiovascular causes (19.1%). Lipid disorder, hemoglobin, serum albumin, β2-M, and IL-6 concentration were independent risk factors for predicting cardiovascular mortality during the 60-month follow-up in hemodialysis patients. Based on the Kaplan–Meier analysis, we realized that patients with a higher interleukin 6 concentration (G2) had a significantly higher cardiovascular mortality rate than patients in G1 (log-rank test p < 0.001). Serum IL-6 concentration was a better predictor of 5-year cardiovascular mortality than high-sensitivity C-reactive protein in hemodialysis patients using low-flux dialyzer reuse (AUC = 0.818; p < 0.001; cut-off value: 8.055 pg/mL, Se = 77.8%, Sp = 78.5%). Conclusion: Serum IL-6 concentration was a better predictor of 5-year cardiovascular mortality than high-sensitivity C-reactive protein in maintenance hemodialysis patients using low-flux dialysis reuse. [ABSTRACT FROM AUTHOR]

We investigate the global exponential stability of equilibrium solutions of a projected dynamical system for variational inequalities. Under strong pseudomonotonicity and Lipschitz continuity assumptions, we prove that the dynamical system has a unique equilibrium solution. Moreover, this solution is globally exponentially stable. Some examples are given to analyze the effectiveness of the theoretical results. The numerical results confirm that the trajectory of the dynamical system globally exponentially converges to the unique solution of the considered variational inequality. The results established in this paper improve and extend some recent works. [ABSTRACT FROM AUTHOR]

The article "Interleukin 6 is a better predictor of 5-year cardiovascular mortality than high-sensitivity C-reactive protein in hemodialysis patients using reused low-fux dialyzers". [ABSTRACT FROM AUTHOR]