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Two new sucrose derivatives, named as cannadica A (1) and cannadica B (2), and eight known compounds, 6′-O-acetyl-3-O-(E)-p-coumaroylsucrose (3), heterophylloside C (4), 6′-O-vanilloylarbutin (5), isotachioside (6), 2,6-dimethoxy-p-hydroquinone 1-O-β-D-glucopyranoside (7), 3,5-dimethoxy-p-hydroquinone 1-O-β-D-glucopyranoside (8), benzyl glucoside (9), and 3,4-dihydroxybenzaldehyde (10) were isolated from the roots of Canna indica L. by various chromatographic methods. Their structures were established by extensive spectroscopic analysis (UV, IR, HR-ESI-MS and NMR) and by comparison of the spectral data with those reported in the literature. Compounds 1-10 were evaluated their antioxidant activity by peroxyl radical absorbance capacity assay. Compounds 4 and 5 exhibited the most peroxyl radical absorbance capacity. At concentration of 1 µM, their ORACROO* values were 4.86 ± 0.39 and 3.11 ± 0.26, respectively, fold-up to that of trolox as an internal standard.

The understanding of the formation of silicate oligomers in the initial stage of zeolite synthesis is important. The use of organic structure-directing agents (OSDAs) is known to be a key factor in the formation of different silicate species and the final zeolite structure. For example, tetraethylammonium ion (TEA+) is a commonly used organic template for zeolite synthesis. In this study, ab initio molecular dynamics (AIMD) simulation is used to provide an understanding of the role of TEA+ in the formation of various silicate oligomers, ranging from dimer to 4-ring. Calculated free-energy profiles of the reaction pathways show that the formation of a 4-ring structure has the highest energy barrier (97 kJ/mol). The formation of smaller oligomers such as dimer, trimer, and 3-ring has lower activation barriers. The TEA+ ion plays an important role in regulating the predominant species in solution via its coordination with silicate structures during the condensation process. The kinetics and thermodynamics of the oligomerization reaction indicate a more favorable formation of the 3-ring over the 4-ring structure. The results from AIMD simulations are in line with the experimental observation that TEA+ favors the 3-ring and double 3-ring in solution. The results of this study imply that the role of OSDAs is not only important for the host–guest interaction but also crucial for controlling the reactivity of different silicate oligomers during the initial stage of zeolite formation.

Dissolved oxygen (DO)-stat fed-batch culture, which allows a high cell density culture of microorganisms under constant DO conditions, was applied to anti-CRP single-chain variable fragment (scFv) production using recombinant Escherichia coli. The DO-stat fed-batch culture was successfully performed under various DO conditions for more than 50 h, resulting in increased scFv production from 0.5 to 0.8 g/L by flask and batch cultures to 2.8–3.0 g/L by the fed-batch culture under the conditions of 5–40% of DO saturation. The formation of inclusion bodies was effectively depressed during DO-stat fed-batch operation; consequently, the solubility of anti-CRP scFv was significantly improved from 36–43% by the flask and batch cultures to 96–98% by the DO-stat fed-batch culture under a wide range of DO conditions. From the kinetic analysis of fed-batch experiments, it was also found that the successful folding of anti-CRP scFv in the cytoplasm occurred when metabolic rates, such as the specific growth rate and specific glucose consumption rate, were relatively low. These results show that the fed-batch culture operated by the DO-stat feeding strategy was effective for the enhanced production of anti-CRP scFv with high solubility.

Ultra-high temperature geothermal wells (>450 °C) have a large potential for increased energy yield as compared to conventional high-temperature geothermal wells (200-300 °C), but several research challenges must be resolved before robust operation in this temperature range can be achieved. In this study, yield- and tensile strength data for several relevant carbon steels and corrosion resistant alloys are generated as a step on the way to enable design of collapse- and tensile capacity for geothermal casings exposed to temperatures up to 500-550 °C. The experiments extend the data set listed in NZS 2403:2015 by providing data for higher temperatures and different material classes. It is found that the carbon steels follow the same near linear decay in strength as the NZS 2403:2015 curves up to 350 °C, and then display a significant drop in tensile strength at higher temperatures, particularly for the lower strength steels. The alloys with high nickel content work harden significantly more than the carbon steels at high temperatures and they tend to retain their strength at temperatures above 350 °C. The tested titanium alloy shows high yield strength and low work-hardening at 500 °C and in contrast to the tested nickel alloys, do not display dynamic strain ageing. © 2020 The Author(s)

Portland based cement is one of the most popular materials used in the civil and construction applications. Reliable computational methods to provide an insight into the underlying mechanics of the major phases of this material are of great interest for cement design. The present work investigated the performance of density functional theory (DFT) calculations using the PBE-D2 method to predict the mechanical, thermodynamic properties of four major phases namely Alite C3S, Belite C2S, tricalcium aluminate C3A and tetracalcium aluminoferrite C4AF. The calculated elastic properties were in a good agreement with available experimental data. In addition, a deeper insight into the electron density of state, spin-polarization, atomic charge, as well as free energy and entropy properties were also presented. Further development is necessary to improve the established DFT models for predicting the mechanical properties of the ferrite phase of Portland clinker.

In our search for cytotoxic constituents from Vietnamese plants, the methanolic extract of Isotrema tadungense was found to exhibit significant cytotoxic effect. Subsequent phytochemical investigation of ethyl acetate fractions of this plant led to isolation of 11 compounds including one new arylbenzofuran rhamnoside namely aristolochiaside (1), two aristololactams (2 and 3), three lignanamides (4–6) and five phenolic amides (7–11). Their structures were elucidated by 1 D and 2 D NMR and HR-QTOF-MS experiments. Among the isolated compounds, aristolochiaside (1), aristolactam AIIIa (2) and N-trans-sinapoyltyramine (10) exhibited strong and selective cytotoxicity on the HeLa human cancer cell line with IC50 values of 7.59 ± 1.03, 8.51 ± 1.73 and 9.77 ± 1.25 μM, respectively.

The stabilized production of anti-CRP single-chain Fv (scFv) antibody using recombinant E. coli by prolonged dissolved oxygen (DO)-stat fed-batch culture was demonstrated, focusing on the supply of nitrogen sources during fed-batch operation. The serious degradation of anti-CRP scFv by intracellular proteases was observed when the fermentation time was prolonged from 50 h to 100 h, which was presumably induced by the insufficient supply of free amino acids. To evaluate the effects of amino acid supply on the proteolysis of anti-CRP scFv, fed-batch experiments using yeast extract (YE)-enriched feeding medium, which had various blend ratios of glucose and YE (G/YE), were performed. By increasing the YE content in the feeding medium, the expression of intracellular proteases was significantly suppressed; consequently, the proteolysis of the scFv production was successfully prevented in 100 h fed-batch culture. The desired G/YE ratio to avoid proteolysis was 1.0 g-glucose/g-YE. The stabilization of scFv production accordingly resulted in the enhanced scFv production from 3.0 g/L in 50 h fed-batch culture to 4.0–5.2 g/L in 100 h fed-batch culture with more than 97% solubility which corresponded to 94.9% of increase in total scFv production by one fed-batch operation.

Pediocin PA-1 is an antimicrobial peptide which has a strongly activity against some Gram – positive pathogens such asListeria monocytogenes, Staphylococcus aureus, Enterococcus faecalis…With the broad inhibitory spectrum as well as pH and temperature stability, pediocin has a potential application in food preservation as well as pharmaceutical industry. For higher manufactory efficiency, pediocin has been expressed in both prokaryote and eukaryote heterologous expression system, mostly on Escherichia coli with different strategies. Here, we show a new strategy to produce pediocin fromEscherichia coliBL21(DE3) system as fusion form by using a vector containing NusA tag. Our results showed that NusA fused pediocin almost presented in soluble form with high efficiency (79.8 mg/l obtained by Ni-NTA purification). After remove the fusion tag, recombinant pediocin showed antimicrobial activity againstListeria monocytogenesATCC 13932 as 23.5×103Au/mg as well as againstEnterococcus faecalis, Lactobacillus plantarum, and Streptococcus thermophilus, especiallyVibrio parahaemolyticus– a Gram-negative bacteria which have not been reported in antimicrobial spectrum of pediocin on Bactibase. Recombinant pediocin is recorded to be stable to a wide range of pH (1-12 for 1 hour) and temperature (100°C for 15 min) as well as sensitive to protease treatment as the nature pediocin. These characteristics opened a prospect of using pediocin as bio-preservative compound in food industry.

In our search for anti-inflammatory constituents from Vietnamese plants, the methanolic extract of Helicteres viscida was found to exhibit inhibitory effect on LPS-induced NO production in RAW264.7 cells. Phytochemical investigation of this plant led to isolation of four sulphated flavones (1���4), including one new compound 5,3���,4���-trihydroxy-7-methoxy-8-O-sulphate flavone (1), and two pregnane-type steroids (5 and 6), including one new compound 7-epi-heligenin B (5). Their structures were elucidated by 1D and 2D NMR as well as HR-QTOF-MS experiments. Among isolated compounds, heligenin B (6) exhibited potent inhibitory effect on LPS-induced NO production in RAW264.7 cells with IC50 of 1.23 �� 0.05 ��M. The activity of 6 was comparable to that of the positive control cardamonin.

This study evaluated the suitability of groundwater quality for domestic use and irrigation in Vinh Chau District, Soc Trang Province, Vietnam. Water samples from 30 domestic-use and 10 irrigation groundwater wells were collected and their physicochemical parameters were analyzed. Results indicated that, based on WHO and Vietnamese standards, the groundwater quality had good suitability, generally to the medium level, but for drinking purposes some areas were found to require water treatment. Six water quality parameters—sodium adsorption ratio, soluble sodium percentage, permeability index, sodium percentage, residual sodium carbonate, and magnesium adsorption ratio—were calculated and employed for evaluating suitability for irrigation, in addition to electric conductivity. The results showed that the six parameters stayed at the permissible level for irrigation, whereas high sodium and salinity were a concern for irrigation. Use of the Piper trilinear diagram to analyze hydrochemical facies and groundwater types showed that the groundwater samples were in the sodium-potassium-chloride-sulfate category and that sodium water type was dominant.

Two new acylated sucroses, (6- O-axetoxyl)- β-d-fructofuranosyl-(2→1)-(6- O-feruloyl- α- d-glucopyranoside (1) and (6- O-axetoxyl)- β-d-fructofuranosyl-(2→1)-(6- O-( E)- p-coumaroyl- α- d-glucopyranoside (2), and four known compounds, 2-(3′,4′-dihydroxyphenyl)-1-propanol-4′- O-[4′′′-hydroxy-3′′′,5′′′-dimethoxybenzoyl-(→6′′)- β-d-fructofuranoside (3), tryptophol glucoside (4), corchonoside C (5), and 2-hydroxy-5-(2-hydroxyethyl)phenyl β-d-fructofuranoside (6), were isolated from the roots of Canna indica L. (Cannaceae). Their structures were determined by extensive analysis of HR-ESI-MS, 1D, and 2D NMR spectral data, as well as by comparison of these with those reported in the literature. Antioxidant activity of compounds 1-6 were evaluated by peroxyl radical absorbance capacity assay. Compounds 1 and 3 neutralized high amounts of peroxyl radical. At a concentration of 1 µM, their ORACROO* values were 3.07 ± 0.15 and 4.27 ± 0.30, respectively, many times greater than that of trolox, which was used as an internal standard. At 10 µM, the peroxyl radical absorbance capacity of compounds 1 and 3 exhibited equivalents to 15.60 ± 0.22 and 24.91 ± 0.43 times the net protection by 1 µM of trolox.

The present study investigated experimentally and numerically the structural behaviour of two chamber extruded profiles in AA6060-T7 alloy subjected to axial crushing under quasi-static loading conditions. Experimental tests were performed (including uniaxial tests, in-plane shear test and plane strain tension tests) to characterize the elastic–plastic, anisotropy and fracture behaviour of the investigated material. The material under investigation exhibited anisotropic properties and isotropic yield models such as von-Mises were not able to predict correctly the shear and plane strain test behaviour. It depicted that the advanced material model with anisotropic Yld2004-18p yield function and ECL criterion was necessary to predict the material tests results (UT, ISS and PST) both in terms of force–displacement curves and ductile fracture. Axial crushing tests were also conducted to investigate the energy absorption capacity of two chamber profiles made of this alloy. A solid element-based numerical model of these component tests was established in the commercial finite element code LS-DYNA, and simulations were run with the calibrated material models and fracture criterion. The predicted force–displacement curves, the energy absorption and fracture were in a good agreement with the experimental results. These results demonstrate that numerical models can be used as a reliable design tool for optimizing aluminium profiles for automotive applications.

The behaviour of square hollow section AA6060 aluminium profiles subjected to quasi-static axial crushing was investigated experimentally and numerically. The profiles were artificially aged to three different tempers (under-aged, peak-aged and over-aged) using two different cooling rates (water quench or air cooling) after the solution treatment, thus obtaining six different materials. The materials’ microstructures were characterized by scanning and transmission electron microscopy and mechanical testing was used to determine the stress–strain curves in uniaxial tension. Axial crushing tests were carried out on profiles made of the six different materials to study the influence of the heat treatment on the energy-absorbing capability of the profile. The nanometre-scale material model NaMo was employed to predict the stress–strain curves of the three water-quenched materials based on the chemical composition and the thermal history. A new feature was introduced in NaMo in order to account for the incubation period, which cannot be ignored for low-alloy materials such as the AA6060 alloy. The stress–strain curves predicted using the improved nano-scale material model showed good agreement with the experimental curves for the three tempers when the incubation period was considered. Using the predicted stress–strain curves in finite element simulations of axial crushing of the profiles, gave excellent predictions of the experimentally obtained force–deformation curves and thus the energy absorption. The results indicate that two-scale simulation based only on chemical composition and thermal history is now possible in designing AA6xxx structural components for safety applications.

In the present study, the behaviour of aluminium rivets in alloy AA7278-T6 during the riveting process when used to join two aluminium plates was investigated experimentally and numerically. It was observed by Hoang et al. that a rivet in alloy AA7278-T6 may fracture in shear when undergoing high pressure during the riveting process. A damage-based failure model was adopted for studying the shear fracture behaviour of the rivet. A calibration procedure of the damage parameters was suggested based on two tests (i.e. material tension tests and rivet compression tests). The model was implemented in the finite element code LS-DYNA as a user-defined subroutine. Numerical results showed that the model seemed to be able to capture the shear fracture mode in the rivets as observed in the tests.

The present paper investigates the fracture mechanisms of AA7278-T6 aluminium self-piercing rivets under compression during the riveting process. First, a microstructure investigation was conducted to disclose the grain structure and the particle distribution of the extruded aluminium alloy. Transmission electron micrographs revealed precipitate free zones along grain boundaries. Uniaxial tensile tests in three different directions with respect to the extrusion direction revealed anisotropy of the alloy in strength and ductility and a change in fracture mode with tensile direction. The behaviour of the alloy under compression was studied experimentally using upsetting tests and self-piercing riveting tests. Micrographs of the deformed specimens provided insight into the influence of the microstructure on the deformation and fracture of the alloy under compression. Second, numerical analyses were carried out using a 2-D axisymmetric model in LS–DYNA in an attempt to investigate the role of different physical variables on the final failure of the rivet. The numerical results revealed that constituent particles, precipitate free zones, and friction between the rivet and plates are important for strain localisation and fracture in the rivet.

The present paper deals with the structural behaviour of self-piercing riveted joints based on aluminium and steel rivets. Two T-components made of two open aluminium profiles in alloy AA6063 temper T4 joined by 6 and 12 rivets, respectively, were designed and tested under quasi-static loading conditions. A new test device was designed to perform the tests of the T-components under two different load cases. Experimental results of the T-components joined by using aluminium self-piercing rivets were then compared with the corresponding components joined by using steel rivets in terms of force-displacement curves, deformation modes of the components as well as rivet failure modes. Further, the experimental results of the T-components based on aluminium rivets were used to validate a resultant-based point-connector model for self-piercing rivets proposed by Hanssen et al. (2010) using shell elements.

The joining of two aluminium plates with an aluminium self-piercing rivet, as discussed by Hoang et al. (2010) , showed that heating to soften the plates to be joined might be used to avoid plastic compression or fracture in the rivet. In the present paper, the mechanical behaviour of self-piercing riveted connections using an aluminium rivet was investigated. Two U-shaped specimens in alloy AA6063-W, obtained by a solution heat treatment of the alloy in temper T4, were joined using an aluminium self-pierce rivet in alloy AA7278-T6. The mechanical behaviour of these connections was tested after 3 and 30 days of natural aging of the riveted specimens. Test results showed that the strength of the aluminium riveted joints tended to stabilize after three days of natural aging. In order to evaluate the process effect (i.e. the effect of the pre-straining of the plates in W temper as the result of the riveting process, and the subsequent natural age-hardening of the plates) on the mechanical properties of the riveted connection, a comprehensive material test programme was carried out. Test results revealed that there is an interaction between the pre-straining and natural aging which lowers the material properties in terms of the flow stress compared to the ‘virgin’ material, i.e. the curve obtained after heat treatment and aging only. Then, the process effect on the mechanical behaviour of the riveted connections was investigated more closely by using a 3D-model generated in LS-DYNA. The combined effect of the pre-straining and natural aging was accounted for in the numerical analyses by means of a user-defined constitutive model. Numerical analyses revealed that it is necessary to consider the combined effect of plastic deformation and aging in order to predict the mechanical behaviour with a reasonable accuracy.

The effect of temperature on the reaction of toluene with hydrogen atoms is interpreted by the RRKM(Marcus–Rice) unimolecular rate theory. It was found that the product distribution changed markedly with temperature in the range of 300–780°K. Methyl-cyclohexadienes and methylcyclohexenes were the main products in the vicinity of room temperature, which were taken over by benzene and ethylbenzene as temperature increased. The calculation based on RRKM theory shows that the experimental results are explained in terms of the effect of temperature on the unimolecular reactions of the chemically activated methylcyclohexadienyl radicals.

Thiophene was subjected to the reaction with hydrogen atom under reduced pressure in the temperature range of 300 – 70°K using a discharge-flow reactor. Butadiene, butenes, n-butane, propylene, and C2 hydrocarbons are the main products, and no formation of sulfur-containing products other than hydrogen sulfide is observed.

Reactions of toluene and hydrogen atoms were carried out at 300–780°K under 6 mmHg pressure, Methylcyclohexadienes and methylcyclohexenes were main products in the vicinity of room temperature, while benzene and ethylbenzene were formed with high selectivities at higher temperatures.

The development of the self-piercing riveting (SPR) technology in recent years has broadened the application of the technology in the automobile industry. However, the SPR process currently utilises high-strength steel rivets; and the combination between steel rivets with an aluminium car body makes recycling a challenge. The possibility of replacing a steel self-piercing rivet with an aluminium one has thus been raised as an interesting topic. Within this framework, the objective of the present paper is to provide an experimental database on the riveting process using an aluminium self-piercing rivet. An experimental programme has been carried out, where two similar sheets in aluminium alloy 6060 in three different tempers (temper W, temper T4, and temper T6) have been joined by using a self-piercing rivet in three different alloys, i.e. 6082-T6, 7108-T5, and 7278-T6. The influence of the die shape on the SPR of aluminium sheets using aluminium rivets was also considered. Conventional rivets and dies according to the Boellhoff standards were employed. The test results were exploited in terms of the riveting force–displacement curves and cross-sectional geometries of the riveted joints. The test data were also used to validate a 2D-axisymmetric model, which was originally developed at SIMLab for modelling the riveting process using a steel rivet. Finally, the mechanical behaviour of a riveted connection using an aluminium rivet under quasi-static loading conditions (i.e. combined pure shear and pure opening loads) was experimentally studied and compared with corresponding tests using a steel rivet in terms of force–displacement curves.

Reactions of toluene and hydrogen atoms were carried out at 300–780°K under 6 mmHg pressure, Methylcyclohexadienes and methylcyclohexenes were main products in the vicinity of room temperature, while benzene and ethylbenzene were formed with high selectivities at higher temperatures.

We investigate the microscopic distributions of sub-band-gap luminescence emission (the so-called D-lines D1/D2/D3/D4) and the band-to-band luminescence intensity, near recombination-active subgrain boundaries in multicrystalline silicon wafers for solar cells. We find that the sub-band-gap luminescence from decorating defects/impurities (D1/D2) and from intrinsic dislocations (D3/D4) has distinctly different spatial distributions, and is asymmetric across the subgrain boundaries. The presence of D1/D2 is correlated with a strong reduction in the band-to-band luminescence, indicating a higher recombination activity. In contrast, D3/D4 emissions are not strongly correlated with the band-to-band intensity. Based on spatially resolved, synchrotron-based micro-X-ray fluorescence measurements of metal impurities, we confirm that high densities of metal impurities are present at locations with strong D1/D2 emission but low D3/D4 emission. Finally, we show that the observed asymmetry of the sub-band-gap luminescence across the subgrain boundaries is due to its inclination below the wafer surface. Based on the luminescence asymmetries, the subgrain boundaries are shown to share a common inclination locally, rather than being orientated randomly., Australian Research Council, Australian Renewable Energy Agency (gramt RND009), National Science Foundation (U.S.). Graduate Research Fellowship (Grant No.1122374), United States. Department of Energy. Office of Science (Contract No. DE-AC02-06CH11357)

WOS: 000371764500032, Here we describe the successfully fabrication of metal nanoparticle crystals by implanting copper (Cu) ions into single zinc oxide (ZnO) crystals with ion energy of 400 keV at ion doses of 1 x 10(16) to 1 x 10(17) ions/cm2. After implantation and post-annealing treatment, the Cu implanted ZnO produces a broad range of luminescence emissions, ranging from green to yellow. A green luminescence peak at 550 nm could be ascribed to the isolated Cu ions. The changes in luminescence emission bands between the initial implant and annealed suggest that the implants give rise to clustering Cu nanoparticles in the host matrix but that the annealing process dissociates these. Numerical modelling of the Cu nanoparticles was employed to simulate their optical properties including the extinction cross section, electron energy loss spectroscopy and cathodoluminescence. We demonstrate that the clustering of nanoparticles generates Fano resonances corresponding to the generation of multiple resonances, while the isolation of nanoparticles results in intensity amplification. (C) 2016 Elsevier B.V. All rights reserved., Vietnam National Foundation for Science and Technology Development (NAFOSTED) [103.03-2014.08], The authors are grateful to Professor Ch. Buchal for the provision of implantation facilities. This research is funded by Vietnam National Foundation for Science and Technology Development (NAFOSTED) under grant number "103.03-2014.08".