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Nanodiamond (ND) has recently emerged as a potential nanomaterial for nanovaccine development. Here, a plant-based haemagglutinin protein (H5.c2) of A/H5N1 virus was conjugated with detonation NDs (DND) of 3.7 nm in diameter (ND4), and high-pressure and high-temperature (HPHT) oxidative NDs of ~40–70 nm (ND40) and ~100–250 nm (ND100) in diameter. Our results revealed that the surface charge, but not the size of NDs, is crucial to the protein conjugation, as well as the in vitro and in vivo behaviors of H5.c2:ND conjugates. Positively charged ND4 does not effectively form stable conjugates with H5.c2, and has no impact on the immunogenicity of the protein both in vitro and in vivo. In contrast, the negatively oxidized NDs (ND40 and ND100) are excellent protein antigen carriers. When compared to free H5.c2, H5.c2:ND40, and H5.c2:ND100 conjugates are highly immunogenic with hemagglutination titers that are both 16 times higher than that of the free H5.c2 protein. Notably, H5.c2:ND40 and H5.c2:ND100 conjugates induce over 3-folds stronger production of both H5.c2-specific-IgG and neutralizing antibodies against A/H5N1 than free H5.c2 in mice. These findings support the innovative strategy of using negatively oxidized ND particles as novel antigen carriers for vaccine development, while also highlighting the importance of particle characterization before use.

Nanostructured lipid carriers (NLCs) are gaining attention as the new generation of lipid vehicles. These carriers consist of saturated lipids with small drops of liquid oil dispersed into the inner lipid matrix and are stabilized by a surfactant. Conventionally, NLC-based drug delivery systems have been widely studied, and many researchers are looking into the composition of NLC properties to improve the performance of NLCs. The membrane fluidity and polarity of self-assembling lipids are also essential properties that must be affected by membrane compositions; however, such fundamental characteristics have not been studied yet. In this study, NLCs were prepared from cetyl palmitate (CP), caprylic triglyceride (CaTG), and Tween 80 (T80). Structural properties, such as particle size and ζ-potential of the CP/CaTG/T80 ternary mixtures, were investigated. Then, the systematic characterization of self-assembly properties using fluorescence-based analysis was applied for the first time to the NLC system. As a final step, the ternary diagram was developed based on the self-assembly properties to summarize the possible structures formed at different compositions. The results showed four states: micelle-like, oil-in-water (O/W) emulsion-like, solid lipid nanoparticle-like, and intermediate (solid-liquid coexistence). For the purpose of making the lipid matrix more liquified, the heterogeneous state and the disordered state of the O/W emulsion-like structure might fulfill the criteria of NLCs. Finally, the ternary diagram provides new information about the assembly state of NLC constituents that could become an important reference for developing high-performance NLCs.

Fe2O3 nanoparticles were synthesized from iron nitrate [Fe(NO3)3·9H2O] by hydrothermal method for Fe-air battery anodes. The crystal structure and morphology of the obtained Fe2O3 powder were studied by x-ray diffraction and scanning electron microscopy. Fe2O3/acetylene black (AB) composite electrodes were fabricated by mixing the synthesized Fe2O3 nanoparticles with AB carbon and were then subjected to electrochemical measurements. Results indicated that the duration of hydrothermal treatment significantly influences the morphology and size of synthesized Fe2O3. The morphology and particle size of Fe2O3 also affect the electrochemical properties of Fe2O3/AB composite electrodes, viz., smaller particles provide greater capacity than larger ones. The resistance of electrodes gradually increases during cycling, thereby causing a decrease in the capacity of Fe2O3/AB electrodes.

NiS is a highly promising transition metal sulfide versatile for a sensor material owing to its superior conductivity and stability, and herein we report its first incorporation into an electrochemical sensor. Because exposure to electrolyte under electrochemical impact can easily deform NiS, thereby decreasing its electro-activity and measurement reproducibility, a strategy for optimally integrating NiS into sensors is critically necessary. For this purpose, NiS was initially firmly affixed to a mechanical pencil lead (MPL) by means of hydrothermal deposition (with the result designated as MPL-NiS). MPL, a commercially available carbon-based material with consistent quality, was adopted to make the sensor cost-effective and easily prepared. Then, to prevent direct exposure of NiS to samples during electrochemical measurement and to make the sensor surface more reactive for wide variety of analytes, reduced graphene oxide (rGO) was electrodeposited on the NiS surface to construct a final structure of MPL-NiS/rGO. In summary, NiS, a p-type semiconductor with positive charge, was effectively composited and sandwiched with negatively charged rGO and MPL by means of mutual electrostatic interaction. When the developed MPL-NiS/rGO sensor was used to separately measure bisphenol A (BPA) and mercury- Hg2+, the sensitivity and sensor-to-sensor reproducibility were comparable with or superior to those of previously reported sensors.

The present work reports on the morphological influence of catalyst on oxygen reduction reaction (ORR). As a catalyst, Prussian blue analog structured nickel hexacyanoferrate (Ni-HCF) with two distinct morphologically controlled frameworks, viz. granular crystalline bulk film and rose-petal like structured thin film having smooth surface, are synthesized via controlled anodization route, and their morphological influence on the ORR is investigated. In addition, the influence of addition of carbon black, which is commonly used as catalytic dispersing support, is also studied on the catalytic mechanism for the ORR. Based on the hydrodynamic voltammetry of the electrocatalytic films on rotating disk electrode, the number of electrons involved in the reduction of an O2 molecule, and the kinetic current density of the reaction are estimated. While the pristine Ni-HCF frameworks based catalyst, regardless of their morphology, demonstrates the direct reduction of O2 with participation of 4 electrons, the frameworks when mixed with carbon black as support diverts the reduction via two steps with participation of 2 electrons at each step. A larger kinetic current density is, however, obtained in the case of granular crystalline bulk film of the Ni-HCF frameworks.

The present work demonstrates the formation of self-aligned nanoporous architecture of gallium oxide by anodization of gallium metal film controlled at −15 °C in aqueous electrolyte consisting of phosphoric acid. SEM examination of the anodized film reveals that by adding ethylene glycol to the electrolyte and optimizing the ratio of phosphoric acid and water, chemical etching at the oxide/electrolyte interfaces can be controlled, leading to the formation of aligned nanotubular oxide structures with closed bottom. XPS analysis confirms the chemical composition of the oxide film as Ga2O3. Further, XRD and SAED examination reveals that the as-synthesized nanotubular structure is amorphous, and can be crystallized to β-Ga2O3 phase by annealing the film at 600 °C. The nanotubular structured film, when used as photoanode for photoelectrochemical splitting of water, achieved a higher photocurrent of about two folds than that of the nanoporous film, demonstrating the rewarding effect of the nanotubular structure...

This work reports on back-electron injection barrier property and electrical charge storing behavior of PEDOT film with and without substituted propylene as terminal group. As a barrier layer, thin polymer film is deposited on TiO 2 particles of DSSC using photo-induced polymerization route. The same piece of DSSC device is used before and after deposition of polymer thin-film for studying the influence of interfacial treatment. The propylene substituted PEDOT treatment of the device demonstrates an enhanced power conversion efficiency from 4.31 to 5.96% whereas the unsubstituted PEDOT treated device shows only the power conversion enhancement from 4.54 to 5.31%. This finding suggests the higher barrier performance of the propylene substituted PEDOT for back-electron injections. Unlike the barrier performance, the propylene substituted PEDOT shows poorer electrical charge storing behavior with specific capacitance of 63.47 F g −1 whereas the unsubstituted PEDOT film achieved 96.84 F g −1 .

This work reports the influence of thermal treatment on electrocatalytic water oxidation/reduction behaviors of one dimensional CoTe nanotube film deposited on FTO substrate from aqueous solution at room temperature. The optimally annealed film at 200 °C demonstrates substantially better electrocatalytic properties, which can be ascribed to the enhanced electrochemical active surface area and electrical conductivity obtained by improving the intergranular connectivity. In addition, the annealed nanotube film demonstrates highly competitive performance to that of many outstanding electrocatalysts for overall splitting of alkaline water to generate hydrogen as green fuel with the oxygen evolution reaction overpotential of 0.37 V (without iR-compensation) for the benchmark current density of 10 mA cm−2.

Hydropower has made a significant contribution to the economic development of Vietnam, thus it is important to monitor the safety of hydropower dams for the good of the country and the people. In this paper, dam horizontal displacement is analyzed and then forecasted using three methods: the multi-regression model, the seasonal integrated auto-regressive moving average (SARIMA) model and the back-propagation neural network (BPNN) merging models. The monitoring data of the Hoa Binh Dam in Vietnam, including horizontal displacement, time, reservoir water level, and air temperature, are used for the experiments. The results indicate that all of these three methods can approximately describe the trend of dam deformation despite their different forecast accuracies. Hence, their short-term forecasts can provide valuable references for the dam safety.

We report the modulation of the dual photo/thermo-responsive multicolor fluorescence from poly( N -isopropyl acrylate) pNIPAM-based nanogels. The thermo-responsive pNIPAM-crosslinked matrix was covalently copolymerized with nitrobenzoxadiazole (NBD) monomers as a Forster resonance energy transfer (FRET) donor and electrostatically conjugated with photochromic spiropyran (SP) dyes as a FRET acceptor. The pristine nanogel emits green fluorescence derived from the NBD moieties; however, the irradiation of the nanogels with UV light led to the transformation of the ring-closed colorless SP moieties to the ring-opened coral-red merocyanine (MC) moieties, resulting in light-pink fluorescent nanogels. Notably, at higher temperatures, the fluorescence of the nanogels was red-shifted and enhanced by the more efficient FRET process. The nanogels were well-distributed in the cellular cytoplasm and showed excellent photochromic function in the subcellular environment for applications as photo-switchable bio-imaging agents and nanothermometers.

Lithium-sulfur (Li–S) batteries are considered promising candidates for next-generation energy storage devices due to their ultrahigh theoretical gravimetric energy density, cost-effectiveness, and environmental friendliness. However, the application of Li–S batteries remains challenging; mainly due to a lack of understanding of the complex chemical reactions and associated equilibria that occur in a working Li–S system. A new approach preparing graphene-based active cathode materials of Li-S battery with spatially confined lithium sulfides is reported. The starting graphene-embedded 2D-MoS2 was synthesized by a solvothermal method in organic solvents followed by the calcination of trapped organic solvent molecules at 800 °C to give graphene single sheets inside the 2D-MoS2 layers with 7 A distance (MoS2-Gr-32.51). Then, it was electrochemically reduced/lithiated at potential 0.01 V vs Li+/Li generating metallic molybdenum and lithium sulfides. As a result, the structure of MoS2 multi-layers collapsed. The graphene multi-layer (ML-Graphene) was left behind and shut the lithium sulfides between the layers. The sizes of Li2Sn (n = 4–6) are bigger than the inter-layer distance of ML-Graphene, and the escape of sulfur/sulfides from the cathode into the electrolyte is physically blocked alleviating shuttle effects. The specific capacity of ML-Graphene/lithium sulfides cathode was high of 1209 mAh/gMoS2-Gr at 0.1 C (1 C = 670 mA/g). The ML-Graphene exhibited the remarkable lithium intercalation capability, and the theoretical calculation has been carried out to give 2231.4 mAh/g. Such high capacity was hybridized with the theoretical capacity of sulfur (1675 mAh/g), and the ML-Graphene composite with dichalcogenides (2D-MoS2) became a promising platform for the cathode of Li-S batteries.

The mining sector faces some of the most difficult sustainability challenges of any industrial sector. The mining sector is remarkably significant to the development of the Asia-Pacific Economic Cooperation (APEC) region, because the majority of global trade and investment in this region depends on this sector. Therefore, the assessment of mining sector sustainability at national and global scales in APEC economies is an important task. So far, however, mining sector sustainability assessment frameworks have only been developed at small scales, such as companies and cities. In this study, therefore, it is proposed an indicator-based sustainability assessment framework (iSAF) to assess mining sector sustainability at national and global scales. In this framework, fuzzy logic was utilized to adequately deal with the uncertainty and vagueness of human expressions. The conventional fuzzy scales were suitably modified in the proposed framework to facilitate confident decision-making by the relevant stakeholders. In order to avoid repeatedly conducting the judgment until the acceptable consistency was obtained, iSAF implemented an innovative theory to deal with unacceptable consistencies in judgment. The proposed iSAF was applied to the mining sector of APEC economies using data from the APEC 2010 Project. As for the results, three important criteria including economic, environmental, and social criteria and twenty significant indicators were appropriately selected to cover the actual situation in the sector. The results showed that iSAF was a suitable framework for preventing uncertainty and vagueness in decision-making. iSAF was found to provide crucial support to decision-makers, not only in identifying and structuring the main components contributing to sustainability, but also in pointing out the factors in which significant investment should be made to effectively improve sustainability.

One of the challenges in obtaining hydrogen economically by electrochemical water splitting is to identify and substitute cost-effective earth-abundant materials for the traditionally used precious-metal-based water-splitting electrocatalysts. Herein, we report the electrochemical formation of a thin film of nickel-based Prussian blue analogue hexacyanoferrate (Ni-HCF) through the anodization of a nickel substrate in ferricyanide electrolyte. As compared to the traditionally used Nafion-binder-based bulk film, the anodically obtained binder-free Ni-HCF film demonstrates superior performance in the electrochemical hydrogen evolution reaction (HER), which is highly competitive with that shown by a Pt-plate electrode. The HER onset and the benchmark cathodic current density of 10 mA cm–2 were achieved at small overpotentials of 15 mV and 0.2 V (not iR-corrected), respectively, in 1 M KOH electrolyte, together with the long-term electrochemical durability of the film. Further, a metal-HCF-electrode-based full...

We investigate aggregation-induced emission (AIE) characters of bulk tetraphenylethene (TPE) derivatives with nonpolar and polar exterior chains. The bulk TPE derivatives with nonpolar dodecyl and polar di(ethylene oxide) chains are in liquid crystal (LC) and crystalline phases, respectively, at room temperature. The mobile LC character of the TPE derivatives in bulk is crucial for high AIE efficiency because the mobile LC character is effective in minimizing the number of undesirable nonemissive local sites in aggregates and inducing a homogeneous zigzag-stacked columnar structure with j-type coupled transition dipoles of the TPE derivatives. The mobile LC characteristics of AIE luminogens can be advantageous for highly efficient solid-state emission.

Horizontal displacement of hydropower dams is a typical nonlinear time-varying behavior that is difficult to forecast with high accuracy. This paper proposes a novel hybrid artificial intelligent approach, namely swarm optimized neural fuzzy inference system (SONFIS), for modeling and forecasting of the horizontal displacement of hydropower dams. In the proposed model, neural fuzzy inference system is used to create a regression model whereas Particle swarm optimization is employed to search the best parameters for the model. In this work, time series monitoring data (horizontal displacement, air temperature, upstream reservoir water level, and dam aging) measured for 11 years (1999–2010) of the Hoa Binh hydropower dam were selected as a case study. The data were then split into a ratio of 70:30 for developing and validating the hybrid model. The performance of the resulting model was assessed using RMSE, MAE, and R 2. Experimental results show that the proposed SONFIS model performed well on both the training and validation datasets. The results were then compared with those derived from current state-of-the-art benchmark methods using the same data, such as support vector regression, multilayer perceptron neural networks, Gaussian processes, and Random forests. In addition, results from a Different evolution-based neural fuzzy model are included. Since the performance of the SONFIS model outperforms these benchmark models with the monitoring data at hand, the proposed model, therefore, is a promising tool for modeling horizontal displacement of hydropower dams.

Sterols such as cholesterol (Chol) and ergosterol (Erg) are known to regulate membrane properties in higher eukaryotes and in lower eukaryotes, respectively. To better understand the modulation of membrane properties by Erg, binary lipid membranes composed of Erg and diacylglycerophosphocholine (PC) were studied in Langmuir monolayer and bilayer vesicle systems. From the excess area measured by pressure-area isotherms, attractive interactions between Erg and saturated PC were significant above the melting temperature (Tm) of PC. Conversely, repulsive interactions were observed at temperatures below Tm. From the analyses of membrane fluidity and polarity using fluorescence probes, similar trends were observed for bilayer systems where Erg had an ordering effect on saturated PC vesicles in the fluid state. However, Chol had a stronger ordering effect than Erg. In unsaturated PC systems, Erg did not alter membrane ordering. These findings demonstrate that the interaction of Erg with the fluid-state PC lipids will maintain lower-eukaryote membranes in a more ordered state, similar to the effect of cholesterol in higher eukaryotes.

Satellite remote-sensing products with high spatial and time resolution are expected to provide alternative data sources for data-sparse regions. This study clarifies if the satellite–gauge product outperforms the satellite-only product by comparing remote-sensing precipitation products: one that incorporates rain gauge data (GSMaP-Gauge) and one that uses satellite only (GSMaP-MVK). The appropriateness of those two commonly used high-resolution products as the input to the conceptual hydrological model Hydrologiska Byråns Vattenbalansavdelning for stream flow prediction was also investigated. In addition, we also analyzed the deviations of model parameters due to the bias in remote-sensing precipitation inputs compared to standard ground measurements. The results indicated that GSMaP-Gauge was superior, with satisfactory to good performances in predicting stream flow in both temperate and subtropical basins (Hyeonsan, Fuji, and Da). However, its performance was slightly worse than GSMaP-MVK in the Upper-Cau basin, which was explained by the poor quality of the adjusted data source due to sparse data and the satellite–gauge blending algorithm of GSMaP-Gauge. Better parameter agreements with the observations of GSMaP-Gauge than GSMaP-MVK were found in the Hyeonsan and Da river basins where GSMaP-Gauge showed almost consistent relationship of monthly rainfall compared to ground measurements.

Bioactive glass-ceramics (BGCs) with the composition of 60SiO2-30CaO-10P2O5 (wt. %) have been synthesized by the hydrothermal method. The BGC samples were prepared at two reaction temperatures of 150 and 220°C, named BGC-150 and BGC-220. The XRD and FTIR analyses highlighted that the degree of crystallinity of BGCs increased linearly with hydrothermal reaction temperature. FE-SEM and TEM results indicated that the surface of BGC samples is covered by the nanosized particles which grow into larger sizes as a function of reaction temperature. The bioactivity of BGCs was investigated by the immersion of powder samples in the SBF solution. The results confirmed the dissolution and the interaction of BGC samples in the SBF solution which led to the formation of a new apatite phase on their surface.

Recently, the graphite based materials have gained interest as excellent platforms to remove aqueous pollutants via adsorption routes. This is given that such materials possess large specific surface area and low density. In the present work, a comparative study of two facile and effective approaches is conventional thermal heating and microwave irradiation methods to fabricate expanded graphite from available flake graphite sources of Vietnam for oil-contaminated water purification. The as-prepared expanded graphite was characterized by using FT-IR, SEM, XRD and BET analysis. The results exhibited that expanded graphite has multilevel pore structures and the surface area of expanded graphite obtained from microwave irradiation and conventional heating was 147.5 (m²/g) and 100.97 (m²/g) under optimal processing conditions. The as-synthesized expanded graphite from the microwave irradiation method was found to have higher adsorption capacities for diesel oil, crude oil, and fuel oil compared to conventional heating method.

This work reports on in-situ doping of Fe(III) redox centers to Ni Co based Prussian blue analogue framework films and their eletrocatalytic performance towards water splitting into molecular hydrogen and oxygen. Uniform and self-supported films of frameworks are deposited onto nickel substrate via anodization in 80 vol % glycerol based aqueous electrolyte containing 0.1 M K3[Co(CN)6] with/without addition of a small amount of [Fe(CN)6]3− as doping precursor. XRD, HR-TEM, STEM and XPS characterization of the film confirmed the doping. Notably, the doped film demonstrated an enhanced electrocatalytic activity towards hydrogen and oxygen evolution reaction in alkaline electrolyte with small overpotentials of 169 and 263 mV, respectively to derive the benchmark current density of 10 mAcm−2. In addition, bulk electrolysis at 10 mAcm−2 demonstrated an improved and well-maintained long-term electrochemical durability of the doped film-based cathode and anode for overall splitting of water.

This work presents an epitaxial deposition of a thin film of single crystal MoTe2 nanorods via electrodeposition at room temperature from aqueous based electrolyte purged with argon. The method allows control over film morphology through deposition potential. In a typical deposition performed at −0.8 V vs Ag/AgCl for 10 min, film comprised of 1D MoTe2 nanorods is obtained, while the deposition at −0.9 V vs Ag/AgCl renders nanoplate like structure. When characterized with FE-SEM, XRD, TEM, SAED and Raman spectroscopy, the film shows uniform deposition of single crystal MoTe2 nanorods particularly with metallic 1 T’ phase. In a preliminary test on feasibility of the nanorod film as anode material for Li-ion storage, a promising result is perceived showing discharge capacity of about 770 mAhg−1 with good electrochemical reversibility.

Liposomes are considered an ideal biomimetic environment and are potential functional carriers for important molecules such as steroids and sterols. With respect to the regulation of self-assembly via sterol insertion, several pathways such as the sterol biosynthesis pathway are affected by the physicochemical properties of the membranes. However, the behavior of steroid or sterol molecules (except cholesterol (Chl)) in the self-assembled membranes has not been thoroughly investigated. In this study, to analyze the fundamental behavior of steroid molecules in fluid membranes, Chl, lanosterol, and ergosterol were used as representative sterols in order to clarify how they regulate the physicochemical properties of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) liposomes. Membrane properties such as surface membrane fluidity, hydrophobicity, surface membrane polarity, inner membrane polarity, and inner membrane fluidity were investigated using fluorescent probes, including 1-(4-trimethylammoniumphenyl)-6-phenyl-1,3,5-hexatriene, 8-anilino-1-naphthalenesulfonic acid, 6-propionyl-2-(dimethylamino) naphthalene, 6-dodecanoyl-2-dimethylaminonaphthalene, and 1,6-diphenyl-1,3,5-hexatriene. The results indicated that each sterol derivative could regulate the membrane properties in different ways. Specifically, Chl successfully increased the packing of the DOPC/Chl membrane proportional to its concentration, and lanosterol and ergosterol showed lower efficiencies in ordering the membrane in hydrophobic regions. Given the different binding positions of the probes in the membranes, the differences in membrane properties reflected the relationship between sterol derivatives and their locations in the membrane.

In the present study, a carbon dot/hemoglobin (CD/Hb) complex is used as a bio-receptor in an optical cholesterol biosensor. This optical sensor detects cholesterol through fluorescence enhancement of CD, which is normally quenched via π–π interactions between CD and Hb in the CD/Hb complex. CD is released from the CD/Hb complex because hydrophobic interactions between Hb and cholesterol are more favorable than π–π interactions between CD and Hb. The CD/Hb complex enabled selective detection of cholesterol within a linear range from 0 to 800 μM, with a limit of detection of 56 μM and a response time of ≤5 minutes in human blood plasma. Compared with other cholesterol sensors, a CD/Hb complex-based biosensor is simple, highly sensitive, selective, rapid, eco-friendly, and cost-effective for cholesterol detection in both biological and environmental samples.

Hf- and Zr-based metal-organic frameworks are highly stable and porous materials that have been attracted in many applications, especially in biomedicine. The materials are commonly synthesized via solvothermal reaction between Hf or Zr salts and organic linkers, however this method requires elongated reaction time as well as results in heterogeneous particles and low yield, which leads to the difficulty for nano MOF synthesis. To overcome these disadvantages, we applied microwave method to enhance the synthetic efficiency and control particle homogeneity of nano UiO-66 framework. The nano MOFs, named Hf-UiO-66 and Zr-UiO-66, with highly homogeneous nanoparticles, very small sizes and high yields could be formed under microwave irradiation within a few minutes. According to the results from XRD, SEM, N2 isotherm sorption, and TGA characterizations, the materials exhibited similar porosity and structure compared to the original framework. Additionally, Hf-UiO-66 and Zr-UiO-66 showed high efficiency for the treatment of curcumin's overdose by adsorbing the drug from aqueous solution with a maximum adsorption capacity up to 463.02 and 466.39 mg g−1, respectively, higher than reported Zr-UiO-66 (393.22 mg g−1). Moreover, the adsorption mechanisms were revealed that the adsorption of curcumin (CUR) by UiO-66 was influenced by defect sites in the MOF structure.

We investigated the mechanism and sensing efficiency of an anthracene-based fluorescent water-content chemosensor (AMG) containing a guanidine moiety in water-miscible organic solvents. Based on spectroscopic and theoretical results, we established that there are two functions of water for AMG in organic solvents, one of which is as a reagent for protonation and the other is in the solvation and stabilization of ionic products, such as protonated AMG (AMGH+) and hydroxide ion. Moreover, the effective solvation and stabilization of ionic products in organic solvents are critical for the mitigation of the deprotonation between them and the relatively high ratio of the fluorescence turn-on AMGH+ species. In 1,4-dioxane with low polarity, AMGH+ and hydroxide ion cannot be effectively solvated, and there is a strong positive correlation between the fluorescence intensity and volumetric fraction of water due to the improved solvation condition caused by the co-existent water. Conversely, the amount of water in polar solvents is less significant, as evidenced by the relatively small increase in the fluorescence intensity upon increasing the water content. This is because ionic products can be stabilized by polar organic solvent molecules without cooperation with water. Conclusively, the solvation and stabilization of ionic products produced by a chemical reaction at a chemical sensing site in a fluorescent chemosensor are important for determining the relative ratio between the fluorescence turn-on and –off species and the overall sensing efficiency of the fluorescent chemosensors.

The purpose of this study is to prepare and characterize the potential edible packaging films based on chitosan and Sonneratia caseolaris (L.) Engl. leaf extract (SCELE) into matrix. The incorporation of SCELE into Chitosan matrix was conducted with various contents (1–3 % wt) and the chitosan-based film samples were investigated. The effects of SCELE on the physical properties and antimicrobial activity of samples were also characterized. The Vietnamese banana fruit was chosen for food preservation and the appearance of banana coated with and without chitosan-based composite films was evaluated. The results indicated that the presence of SCELE can improve the antimicrobial activities, water vapor barriers while a significant decrease in light transmittance was found. Furthermore, the tensile strength and thermal stability were not affected by the addition of 2 % wt SCELE. Bananas coated with composite film based on chitosan matrix and SCELE had longer life time than control sample and those coated with pure chitosan film, indicating that the combination of SCELE into chitosan matrix brings potential application for active edible food packaging.

There is mounting concern about how to support decision-makers in driving sustainable water resources management; science needs to support the decision-making process to promote evidence-based decisions. To this end, sustainability assessment is considered a useful technique, which provides enough information to assist management. This study proposed a groundwater sustainability assessment framework, which is developed from a regular sustainability assessment approach and analytical hierarchy process (AHP). In the proposed framework, the three main pillars (environmental, social, and economic) of the concept of sustainability were considered the three important sustainability criteria. Hence, we demonstrated the proposed framework for a Hanoi case study with focus on the environmental sustainability criterion. The concept of AHP was used to create the main sustainability components (the three criteria, associated with their aspects and indicators) of a hierarchy, which appropriately cover environmental sustainability issues of groundwater resources in the target area. Based on the available reliable data of the current problems in Hanoi, we proposed three main sustainability aspects (quantity, quality, and management) and, accordingly, selected their twelve environmental sustainability indicators. To determine a reasonable sustainability assessment, we considered a conventional linear and non-linear relationship between the indicators and the corresponding sustainability indices. As for the results from the Hanoi case study, the environmental sustainability indices obtained from using a combined linear and non-linear relationship case appropriately reflect the current situation, that is, the environmental sustainability assessment is close to reality. The sustainability indices of the quantity, quality, and management aspects of groundwater were appropriately assessed at acceptable levels, resulting in Hanoi being rated at the acceptable level in the final environmental sustainability index. The variability of the environmental sustainability indices indicated that the current groundwater abstraction networks are heavily concentrated in a few specific areas in Hanoi, which is not optimal for utilizing the rich natural recharge resources of the area. Improvement of the current poor groundwater quality and strict enforcement of environmental regulations are essential to enhancing the environmental sustainability and, more importantly, to drive Hanoi towards sustainable groundwater resources.

The priority-based traffic light controlling system at an intersection dedicates right-of-way to the highest priority direction. The system is applied for urban traffic system in Vietnam, where various types of vehicles run in close proximity to one another, needs a traffic model suitable to determine the priority of directions going through intersection. The paper has studied current traffic models, microscopic and macroscopic traffic flow models as well as three-phase traffic model, to propose spatio-temporal traffic statistics model. The paper considers red light as a traffic obstacle causing moving jam behind traffic light. The proposed spatio-temporal traffic statistics model studies traffic flow on a road segment bounded by two intersections, where various types of vehicles travel. The spatio-temporal traffic statistics model represents the road surface area occupied by vehicles at locations and over time as spatio-temporal histograms. The expectation of histogram is a factor determining the priority of direction going through intersection.

This work reports on designing of first successful MOF-sensitizer based solid-state photovoltaic device, perticularly with a meaningful output power conversion efficiency. In this study, an intrinsically conductive cobalt-based MOFs (Co-DAPV) formed by the coordination between Co (II) ions and a redox active di(3-diaminopropyl)-viologen (i.e., DAPV) ligand is investigated as sensitizer. Hall-effect measurement shows p-type conductivity of the Co-DAPV film with hole mobility of 0.017 cm2 V–1 s–1, suggesting its potential application as hole transporting sensitizer. Further, the energy levels of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) of Co-DAPV are well-matched to be suitably employed for sensitizing TiO2. Thus, by layer-by-layer deposition of hole conducting MOF-sensitizer onto mesoporous TiO2 film, a power conversion efficiency of as high as 2.1% is achieved, which exceeds the highest efficiency values of MOF-sensitized liquid-junction solar cells ...

This work reports a facile solution based chemical transformation of thin film of CdCO3 cuboids into Cd-based Prussian blue analogue structured thin film with controlled redox-state by manipulating the anion exchange reaction between the solid film and the aqueous solution of K3[Fe(CN)6] at 60 °C. The progress of the transformation reaction is monitored via electron microscopy, X-ray difractometry and X-ray photoelectron spectroscopy. Based on the scenario of the reaction progress revealed by these analysis, the CdCO3 cuboids are first found to be transformed into the smaller cuboids of cadmium ferricyanide, which, on further reaction, are transformed into the cadmium ferrocyanide cuboids. Thus, by controlling the redox-state of the Fe-metal center on the frameworks, the electrocatalytic activity of the frameworks on oxygen reduction reaction (ORR) is studied. The electrocatalytically inert CdCO3 cuboids after transformation to the frameworks with Fe3+-centers demonstrate an enhanced catalytic activity on ORR, while the Fe2+-centers of the frameworks are found to relegate the catalytic activity, thereby manifesting the redox-sate modulated ORR activity of the frameworks. To the best of the authors' knowledge, this is the first report of this kind on redox-state specific ORR activity.

In the present study, a solution-processed organic semiconductor based on indolocarbazole derivative (heptazole) is introduced as a p-type donor material for a bulk-heterojunction photovoltaic device. The heptazole has an optical band gap of 2.97 eV, and its highest occupied molecular orbital-lowest unoccupied molecular orbital energy levels are compactable with the PC60BM to construct a donor-acceptor heterojuction for energy harvesting and transfer. When the bulk-heterojunction photovoltaic devices consisting of ITO/PEDOT:PSS/heptazole:PC60BM/Al with different blending ratio of heptazole:PC60BM were constructed, the cell with 1:1 blending ratio exhibited the best power conversion efficiency. Further, when an indoline organic dye (D149) was introduced as an interfacial modifier to the above donor/acceptor bulk heterojunction, the device demonstrated an enhanced overall power conversion efficiency from 1.26% to 2.51% hence demonstrating enhancement by the factor of 100%. The device was further characterized using electronic absorption spectroscopy, photoluminescence spectroscopy, electrochemical impedance spectroscopy, and the photovoltage decay kinetics. These studies reveal that the enhanced power conversion efficiency of the device is due to the enhanced charge transfer with the complementary light absorption feature of the interfacial D149 dye molecules.

One of causes of repeated traffic congestion at crossroads in Hochiminh City is the unreasonableness of the current system controlling traffic lights that switches lights at fixedly programmed time points. In several cases, vehicles are compelled to stop at stop line while nothing travels on front crossroad, and emergency vehicles can not overpass crowd of vehicles stopping in front of traffic lights. Moreover, the too slow movement of vehicles within crossroad due to conflict of directions is also a cause of congestion and jam. This study proposes an approach, termed the approach to priority-based controlling traffic lights, to serving as a module of traffic light system. The approach eliminates the conflict of vehicles moving within crossroad to decrease the time passing crossroad. Traffic lights are switched according to the priority of directions to reduce the thickness of vehicles in front of traffic lights of directions. As a result, the approach prevents congestion within crossroad and in front of traffic lights at flows entering crossroad.

The present study reports a facile synthetic route for thin film formation of a self-standing 1-D structured array of cobalt hexacyanoferrate crystals using an aqueous solution based ion exchange transformation approach. For this, the cobalt hydroxycarbonate 1-D structured array film was used as a sacrificial precursor template for the ion exchange reaction in aqueous K3[Fe(CN)6] solution. By controlling the reaction, 1-D structured array film, or particulate structured film of the cobalt hexacyanoferrate crystals could be obtained, which thus offered possibilities on morphology-dependent property engineering. The films before and after the ion exchange reaction were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffractometry, energy dispersive X-ray analysis (EDX) and X-ray photoelectron spectroscopy (XPS). Further, electrochemical study of the films was performed using voltammetry, and electrochemical impedance spectroscopy. The study reveals the morphology-dependent electrocatalytic property of the cobalt hexacyanoferrate crystal film on water-oxidation. The 1-D structured array film of the cobalt hexacyanoferrate crystals has demonstrated superior electrocatalytic performance on water-oxidation from alkaline and neutral electrolytes, which is competitive to the catalytic performance demonstrated by many outstanding water-oxidation catalysts.