We investigate the mechanical, electronic, and optical properties of monolayer GeX (X= S, Se, and Te) with γ structure based on density-functional theory calculations. We find that the mechanical ...anisotropy of γ-GeS is higher than those of γ-GeSe and γ-GeTe, because of its strongest ionic bond. In the unstrained case, γ-GeX is an indirect-gap semiconductor with the Mexican-hat (MH) dispersion in the valence band. By applying tensile and biaxial strains, both energy band gap and valley positions are controlled. On the other hand, by applying an external electric field, the energy band gap is decreased to zero because of the downward interlayer band. We also find that the in-plane optical absorptions of monolayer γ-GeX in the visible-light region are comparable to that of the monolayer transition metal dichalcogenides such as MoS2. Due to the unique structure in the z direction, the monolayer γ-GeX also shows a high value of the out-of-plane optical absorptions. The strain engineering significantly modifies the optical absorption in the visible light, while the effect of the external electric field on the optical properties is weak. Our results will be helpful to design the electro-optical devices based on monolayer materials with MH band.
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•Monolayer GeX (X = S, Se, and Te) shows an indirect-gap semiconductor with the Mexican-hat dispersion in the valence band.•Both energy band gap and valley positions can be controlled by applying strains.•Energy band gap is decreased to zero by applying an external electric field.•Strain engineering significantly modifies the optical absorption in visible light.
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•ZnO nanorods were prepared by galvanic effect assisted hydrothermal process.•Gold nanoparticles were decorated on the as-prepared nanorods by sputtering method.•The Au nanoparticles ...enhance photoluminescence, Raman scattering and photocatalytic properties of ZnO nanorods.•ZnO@Au SERS substrates offer high enhancement factor, high uniformity, and recyclability.
Raman is a very useful tool to identify chemical substances. However, Raman signal is normally not very strong and hence it is important to fabricate surface enhance Raman scattering (SERS) substrates of good repeatability and high enhancement factor. In this study, ZnO nanorods were prepared by a facile hydrothermal process assisted with galvanic effect. Gold nanoparticles were decorated on the as-prepared nanorods by sputtering method. The results showed that the Au nanoparticles enhance photoluminescence, Raman scattering and photocatalyst properties of ZnO nanorods. The ZnO@Au based SERS substrate showed high enhancement factor and can detect methylene blue at low concentration of 10–9 M. In combination with self cleaning under UV irradiation, the ZnO@Au SERS substrates can be reusable and hence it is promising for quantitative analyzing based on Raman scattering.
Fifteen steroids, including two new compounds, leptosteroid (1) and 5,6β-epoxygorgosterol (2), were isolated and structurally elucidated from the Vietnamese soft coral Sinularia leptoclados. Their ...cytotoxic effect against a panel of eight human cancer cell lines was evaluated using sulforhodamine B (SRB) method. Significant cytotoxicity against hepatoma cancer (HepG2, IC50=21.13±0.70 µM) and colon adenocarcinoma (SW480, IC50=28.65±1.53 µM) cell lines were observed for 1 and against acute leukemia (HL-60, IC50=20.53±2.26 µM) and SW480 (IC50=26.61±1.59 µM) for ergost-5-en-3β,7β-diol (8). In addition, 3β,7β-dihydroxyergosta-5,24(28)-diene (13) showed significant cytotoxic activity on all tested cell lines with IC50 values ranging from 13.45±1.81 to 29.01±3.21 µM.
In recent years, solar power has developed significantly in Vietnam, making an important contribution to ensuring energy conservation and decreasing greenhouse gas exposure. Recently, Vietnam has ...experienced impressive growth in the solar and wind energy sectors, showing the high potential of using renewable electricity in addressing energy needs. The target of this study was to construct a fuzzy multicriteria decision-making, model including strengths-weaknesses-opportunities-challenges (SWOC) analysis, the fuzzy analytic hierarchy process (F-AHP) model, and the weighted aggregates sum product assessment (WASPAS) model, to select the location of a solar power plant in south Vietnam. The proposed fuzzy multicriteria decision-making model (MCDM) model is the first solar power plant location selection in southern Vietnam that utilizes literature reviews and expert interviews. Moreover, this is the first study to provide a case study on evaluating locations during solar power plant location selection that utilizes a combination of the SWOC, FAHP, and WASPAS models. The findings of this study provide valuable knowledge for the assessment and selection of suitable locations for renewable energy projects, including both solar power energy projects and other renewable energy projects.
Due to the high-cost and limitations of current wound healing treatments, the search for alternative approaches or drugs, particularly from medicinal plants, is of key importance. In this study, we ...report anti-inflammatory and wound healing activities of the major calophyllolide (CP) compound isolated from Calophyllum inophyllum Linn. The results showed that CP had no effect on HaCaT cell viability over a range of concentrations. CP reduced fibrosis formation and effectively promoted wound closure in mouse model without causing body weight loss. The underlying molecular mechanisms of wound repair by CP was investigated. CP markedly reduced MPO activity, and increased M2 macrophage skewing, as shown by up-regulation of M2-related gene expression, which is beneficial to the wound healing process. CP treatment prevented a prolonged inflammatory process by down-regulation of the pro-inflammatory cytokines-IL-1β, IL-6, TNF-α, but up-regulation of the anti-inflammatory cytokine, IL-10. This study is the first to indicate a plausible role for CP in accelerating the process of wound healing through anti-inflammatory activity mechanisms, namely, by regulation of inflammatory cytokines, reduction in MPO, and switching of macrophages to an M2 phenotype. These findings may enable the utilization of CP as a potent therapeutic for cutaneous wound healing.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Two new pyrrole oligoglycosides, plancipyrrosides A and B (1 and 2), were isolated from methanol extract of the Vietnamese starfish Acanthaster planci using various chromatographic procedures. Their ...structures were elucidated by spectroscopic methods including one and two dimensional (1D- and 2D)-NMR and Fourier transform ion cyclotron resonance (FT-ICR)-MS. The finding of 1 and 2 represents the third case of pyrrole oligoglycosides obtaining reported to date. Moreover, plancipyrroside B (2) exhibits a potent inhibitory effect on lipopolysaccharide (LPS)-induced nitric oxide (NO) production in RAW264.7 cells with IC50 of 5.94±0.34 µM, whereas plancipyrroside A (1) shows this inhibitory activity with IC50 of 16.61±1.85 µM.
This article investigates the use of the galactic swarm optimization algorithm in searching for parameters of a convolutional neural network for flood susceptibility mapping. Ha Giang province, the ...mountainous area of Vietnam, was chosen as a case study because of the frequent occurrence of floods. From this study area, 11 predictor variables and historical flood locations were selected to build up the training datasets, in which each sample is prepared in the 3D form of (height × width × channels or variables) = (5 × 5 × 11), (7 × 7 × 11), and (9 × 9 × 11), respectively for three experiments. The model performance was assessed by root mean square error, area under the receiver operating characteristic (AUC), and overall accuracy (OA). The results showed that the examined model significantly improved the classification accuracies: OA = 83.093, AUC = 0.917; OA = 83.726, AUC = 0.923; and OA = 82.791, AUC = 0.908 for the three training datasets in comparison to benchmarked classifiers, and this model can be considered as an alternative solution for flood susceptibility mapping.
•A grid-scale temporal downscaling approach based on scale-invariance is proposed.•Sub-daily extreme rainfall intensities are estimated under climate change.•The approach is applied to case studies ...with a relatively high station density.
Canada.
Intensity-duration-frequency curves need to be updated to account for the potential effect of climate change. However, sub-daily regional climate model (RCM) simulations required for this purpose are commonly unavailable. The scaling approach is often applied for temporal downscaling of point daily precipitation; nevertheless, difference in spatial scale between simulations and observations may complicate its application at the grid scale. This study proposes a grid-scale temporal downscaling approach for estimating sub-daily gridded extreme rainfall intensity under climate change at regions with a relatively high station density. The approach uses daily annual maximum rainfall intensity series from RCM simulations and grid-scale scaling properties from observations. The study evaluates two methods for estimating gridded scaling exponents needed in temporal downscaling. The assessment is performed on observation-based and RCM-based temporally downscaled quantiles. The effect of temporal downscaling and bias correction on sub-daily quantiles and relative changes is also analysed. The approach is applied to three case studies across Canada.
Piecewise simple scaling is found over the study domains, indicating caution in using simple scaling. The performance of the approach in estimating sub-daily observation-based gridded rainfall intensity quantiles is suitable, with preference for point to grid transfer at the annual maximum series stage. Bias correction is necessary for properly estimating sub-daily RCM-based quantiles, presenting less impact on relative changes.
Stretchable and wearable sensor technology has attracted significant interests and created high technological impact on portable healthcare and smart human–machine interfaces. Wearable ...electromechanical systems are an important part of this technology that has recently witnessed tremendous progress toward high‐performance devices for commercialization. Over the past few years, great attention has been paid to simultaneously enhance the sensitivity and stretchability of the electromechanical sensors toward high sensitivity, ultra‐stretchability, low power consumption or self‐power functionalities, miniaturisation as well as simplicity in design and fabrication. This work presents state‐of‐the‐art advanced materials and rational designs of electromechanical sensors for wearable applications. Advances in various sensing concepts and structural designs for intrinsic stretchable conductive materials as well as advanced rational platforms are discussed. In addition, the practical applications and challenges in the development of stretchable electromechanical sensors are briefly mentioned and highlighted.
Stretchable electromechanical sensors that can monitor physical and mechanical stimuli generated by the human body are of considerable interest. The design of eletromechanical sensors based on appropriate rational structures and materials will enable the development of ultrasensitive and ultrastretchable sensing devices for human‐activity monitoring, portable healthcare, and smart human–machine interfaces.
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