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Complementary to hydrophobic five membered ring β-amino acids (e.g. ACPC), β-sugar amino acids (β-SAAs) have found increasing application as hydrophilic building blocks of foldamers and α/β chimeric peptides. Fmoc-protected β-SAAs [e.g. Fmoc-RibAFU(ip)-OH] are indeed useful Lego elements, ready to use for SPPS. The removal of 1,2-OH isopropylidene protecting group increasing the hydrophilicity of such SAA is presented here. We first used N3-RibAFU(ip)-OH model compound to optimize mild deprotection conditions. The formation of the 1,2-OH free product N3-RibAFU-OH and its methyl glycoside methyl ester, N3-RibAFU(Me)-OMe were monitored by RP-HPLC and found that either 50% TFA or 8 eqv. Amberlite IR-120 H+ resin in MeOH are optimal reagents for the effective deprotection. These conditions were then successfully applied for the synthesis of chimeric oligopeptide: -GG-X-GG- [X=RibAFU(ip)]. We found the established conditions to be effective and—at the same time—sufficiently mild to remove 1,2-O-isopropylidene protection and thus, it is proposed to be used in the synthesis of oligo- and polypeptides of complex sequence combination.

Hydrophobic porous polymeric materials have attracted great interests recently as potential candicate for oil-water separation due to their high selectivity and sorption capacity. Herein, we present a green, simple and cost-effective method to change hydrophilic melamine formaldehyde (MF) foam to hydrophobic carbon nanotubes (CNTs) coated MF foam through an immersion process. The MF foam was produced from the MF resin which was synthesized in a laboratory by a condensation reaction between melamine and formaldehyde under alkaline condition with a molar ratio of melamine to formaldehyde of 1:3. The MF foam has an open-cell structure with the average pore diameter of 350 m, density of 25 kg •m-3 and porosity of 98 %. The as-prepared CNTs-coated MF foam exhibits high sorption capacity (23–-66 g/g) for oils and organic solvents, good recyclability and high selectivity.

Korea is considered one of the original centers of Chrysanthemum species, which are important flower crops due to their ornamental and economic values. At present, the genetic resources in wild Chrysanthemum have not been fully exploited. In this study, we evaluated the morphological characteristics and chromosome analysis using forescence in situ hybridization (FISH) technique in four wild Chrysanthemum species to better understand the relationships among species and their evolutionary adaptations to environmental conditions. Although there were some similarities in leaf and flower characteristics, there was high overall variation among the investigated species based on our analysis. Flower diameters ranged from 1.57 ± 0.07 cm (A102) to 3.10 ± 0.10 cm (A7). Also, the RGB values of the white flowers of species A7 were higher than those of the yellow flowers of species A5, A102, and B6. The longest leaf length was observed in species A5 (8.14 ± 0.10 cm), which was dark in color on the upper leaf side, whereas A102 exhibited the shortest leaf length (5.67 ± 0.28 cm) and width (3.20 ± 0.20 cm). FISH karyotype analysis showed that one pair of 5S and three pair of 18S rDNA were observed in all investigated species. The number and distribution pattern of rDNA showed similar arrangement in A5, A102, and B6. One pair of 18S rDNA signals were detected on the terminal region of the short arm chromosomes 3, 7, and 8, respectively. One pair of 5S rDNA signal was located in the interstitial region of chromosome 4. For the A7 species, 5S rDNA were detected in the long arm of chromosome 7 and one pair of 18S rDNA were found in the short arm of chromosomes 2, 5, and 6. According to the results, this study provides basic knowledge on the relationships between the evolution and genomics of Chrysanthemum traits, which are especially important for selecting donor and recipient plants in modern Chrysanthemum breeding programs.

Chrysanthemum boreale (Asteraceae) is a wild flowering plant that has both ornamental and herbal uses. In the present study, colchicine was used as a chemical mutagen to induce polyploidy using in vitro shoots, which were cultured from C. boreale (2n = 2x = 18) nodal segments, and the efficacy of various colchicine concentrations and treatment durations were investigated. The results demonstrated that the induction of tetraploid plants by colchicine treatment were clearly successful. A total of 21 tetraploid and 110 chimera plants were identified using the chromosome counting method, and the colchicine concentrations of 200 ppm (48 h) and 300 ppm (12 and 24 h) were the most effective for inducing tetraploidy. Details about the successful induction, morphological characteristics, and cytology of the polyploids are described and compared with those of control plants. The tetraploid plants exhibited thicker and larger leaves, as well as larger and fewer stomata than the diploid plants. In this study, the polyploid plants of Chrysanthemum were induced successfully using colchicine treatment. This procedure contributed to the improvement of high-value species in the Chrysanthemum breeding program.

Compost application can increase plant nutrient availability. But the effect of compost on nutrient availability may depend on a number of factors. In this study, the effect of application method (mulch layer or mixed into the soil) and combination with inorganic fertiliser on soil P pools and available N was investigated. Soil was filled in microcosm with six treatments, including control, vermicompost layer with or without fertilisers (CL, CL/F), bulk soil mixed with inorganic fertiliser alone (F), vermicompost alone (CM) and both of inorganic fertiliser and vermicompost (CM/F). The microcosms were incubated in the dark for 3 weeks. Citrate P, HCl P and resin P were the highest in F, but MBP was higher in CM and CM/F. Citrate P and HCl P were about three- and six-fold higher in CM and CM/F than in CL and CL/F. Available N was the highest in CL/F and 20% higher in CL than in CM. Vermicompost mixed into soil slightly increased soil nutrient availability compared to unamended soil but had little effect when placed on the soil surface. Vermicompost mixed into soil with inorganic N and P could be used to minimise loss of N and P after inorganic fertiliser addition and thereby provide a longer-lasting nutrient supply for plants.

In the search of smarter routes to control the conditions of N-heterocyclic carbene (NHCs) formation, a two-component air-stable NHC photogenerating system is reported. It relies on the irradiation at 365 nm of a mixture of 2-isopropylthioxanthone (ITX) with 1,3-bis(mesityl)imidazoli(ni)um tetraphenylborate. The photoinduced liberation of NHC is evidenced by reaction with a mesitoyl radical to form an NHC-radical adduct detectable by electron spin resonance spectroscopy. The NHC yield can be determined by 1 H NMR spectroscopy through the formation of a soluble and stable NHC-carbodiimide adduct. To deprotonate the azolium salt and liberate the NHC, a mechanism is proposed in which the role of base is played by ITX radical anion formed in situ by a primary photoinduced electron-transfer reaction between electronically excited ITX (oxidant) and BPh4 - (reductant). An NHC yield as high as 70 % is achieved upon starting with a stoichiometric ratio of ITX and azolium salt. Three different photoNHC-mediated polymerizations are described: synthesis of polyurethane and polyester by organocatalyzed step-growth polymerization and ring-opening copolymerization, respectively, and generation of polynorbornene by ring-opening metathesis polymerization using an NHC-coordinated Ru catalyst formed in situ.

Ionic liquids (ILs) may have various applications as less hazardous solvents because of their thermal stabilities and low vapor pressures. However, it is challenging to remove heat from large amount because of IL’s high viscosity and low vapor pressure when cooling failure or abnormal reaction occurs. Because chemical processes using ILs on an industrial scale are still in the early phase of development, it is important to assess the associated thermal hazards of chemical process using ILs. This work proposes a systematic approach of analyzing thermal hazards of chemical process using ILs, based on the approach proposed by Stoessel and analyze the cellulose dissolution process using ILs containing impurities as a test case. Copper oxide, which might be contaminated from wood chips, was chosen as a model impurity. To analyze the thermal hazards of cellulose dissolution process using ILs, thermal analysis using small-scale reaction calorimeter, differential scanning calorimeter and thermogravimetry–differential thermal analysis–mass spectrometry were performed. From these results, reaction heat and heat value of ILs and its mixture were low, while CuO lowers the decomposition temperature of ILs and produces flammable gases. From these trials, exothermal reaction was not observed, while flammable gaseous products might be produced in vapor phase in the reactor.

Little is known about the effect of long-term P fertilisation on soil P pools and how they are influenced by straw addition and plant growth. Two experiments were carried out with soil which had been amended with 0, 10 and 20 kg P ha−1 for 7 years (referred to 0P, 10P, 20P). In experiment 1, soil was incubated moist for 4 months without or with 5 g kg−1 barley straw (C/P 255). Then wheat was grown for 4 weeks. In experiment 2, wheat was grown for 5, 10 and 15 weeks. HCl P, citrate P, resin P and microbial biomass P (MBP) were two-fold higher with 20P and 10P than 0P. After 4 months compared to 10 days, HCl P and citrate P were 25% lower with straw, but unchanged without straw. Resin P and MBP were two-fold higher. With 10P and 20P after 4-week wheat growth, citrate P was 25% higher and HCl P 25% lower. Plant P uptake was higher with straw, In experiment 2 after 10 and 15 weeks compared to the start at 10P and 20P, HCl P and citrate P were reduced by 20%. Plant P uptake was smaller than the decrease in HCl and citrate P. The greater P uptake by wheat in soil with straw indicates that microbial biomass P is an important P source for plants. In P amended soil, wheat mobilised HCl and citrate P, but only took up a fraction of the mobilised P.

The Province of Khanh Hoa, Vietnam, is located in the western South China Sea and boasts a shoreline of 385 km and many islands. Previous studies have indicated the extreme diversity and abundance of coral reefs in its waters as compared with other coastal provinces of Vietnam. A study on the resilience of coral reefs against increased surface water temperature and anthropogenic impact is conducted at 19 reef sites in 2015. At each site, a series of parameters (e.g., coral covers, genus diversity, and coral recruitment, substratum heterogeneity, depth, water exchange level, and sediment deposit and water temperature) are measured quantitatively or semi-quantitatively. The measured data are rated based on the relationship between the parameter values and coral susceptibility; the consideration that reef health reflects the biological capability to adapt to environmental changes and the recruitment potential if bleached; and positive or negative influences of physical factors in the mitigation of thermal stress and protecting corals from bleaching. A cumulative analysis enables researchers to divide the studied reefs into four categories based on varying levels of reef health to support resilience, recovery, and vulnerability in the case of increased water temperature. Relevant management interventions for each category and other supporting activities are suggested to enhance management effectiveness and to plan the rehabilitation of coral reefs for biodiversity conservation and touristic development, taking into account the involvement of related stakeholders.

International audience; Although N-heterocyclic carbenes (NHCs) have brought profound changes in catalytic organic synthesis, their generation generally requires an inert atmosphere and harsh conditions. To overcome these limitations, an air-stable NHC photogenerator has been developed involving two mild components: 1,3-bis(mesityl)imidazolium tetraphenylborate (IMesH+BPh4−) and electronically excited isopropylthioxanthone (ITX). In this study, the photochemical mechanism is investigated via the accurate identification of the transient species and photoproducts. Electron transfer reaction between the excited triplet state of ITX and BPh4− is demonstrated as being the primary photochemical step. Nanosecond laser spectroscopy shows an efficient quenching and the formation of the expected ITX radical anion. The oxidized borane species is not observed, suggesting that this short-lived species could dissociate very rapidly to give the phenyl radical – successfully identified using electron paramagnetic resonance – and triphenylborane. As regards the final photoproducts, 1H and 13C NMR spectroscopies support the formation of the targeted NHC, 1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene (IMes), suggesting the occurrence of a subsequent proton transfer reaction between ITX radical anion and imidazolium cation (IMesH+). Gas chromatography-mass spectrometry reveals three other products: biphenyl, isopropylthioxanthene and ITX. Their formation can be reconciled with a 2-step mechanism of photoinduced electron/proton transfer reactions. 11B NMR spectroscopy demonstrates that the main organoboron photoproduct is diphenylborinic acid formed by oxidation of BPh3. Due to its Lewis acidity, Ph2BOH can react with IMes to yield an NHC–boron adduct.

This study presents a comprehensive analysis of the major and trace element, mineral, and Sr, Nd, Pb and Mg isotopic compositions of late Cenozoic intraplate basaltic rocks from central and southern Vietnam. The Sr, Nd, and Pb isotopic compositions of these basalts define a tight linear array between Indian mid-ocean-ridge basalt (MORB)-like mantle and enriched mantle type 2 (EM2) components. These basaltic rocks contain low concentrations of CaO (6.4–9.7 wt%) and have high Fe/Mn ratios (> 60) and FeO/CaO–3MgO/SiO2 values (> 0.54), similar to partial melts derived from pyroxenite/eclogite sources. This similarity is also supported by the composition of olivine within these samples, which contains low concentration of Ca and high concentrations of Ni, and shows high Fe/Mn ratios. The basaltic rocks have elevated Dy/Yb ratios that fall within the range of melts derived from garnet lherzolite material, although their Yb contents are much higher than those of modeled melts derived from only garnet lherzolite material and instead plot near the modeled composition of eclogite-derived melts. The Vietnamese basaltic rocks have lighter δ26Mg values (− 0.38 ± 0.06‰) than is expected for the normal mantle (− 0.25 ± 0.07‰), and these values decrease with decreasing Hf/Hf* and Ti/Ti* ratios, indicating that these basalts were derived from a source containing carbonate material. On primitive mantle-normalized multi-element variation diagrams, the central Vietnamese basalts are characterized by positive Sr, Eu, and Ba anomalies. These basalts also plot within the pelagic sediment field in Pb Pb isotopic space. This suggests that the mantle source of the basalts contained both garnet peridotite and recycled oceanic crust. A systematic analysis of variations in geochemical composition in basalts from southern to central Vietnam indicates that the recycled oceanic crust (possibly the paleo-Pacific slab) source material contains varying proportions of gabbro, basalt, and sediment. The basalts from south-central Vietnam (12°N–14°N) may be dominated by the lowest portion of the residual slab that contains rutile-bearing plagioclase-rich gabbroic eclogite, whereas the uppermost portion of the recycled slab, including sediment and basaltic material with small amounts of gabbro, may be a major constituent of the source for the basalts within the central region of Vietnam (14°N–16°N). Finally, the southern region (10°N–12°N) contains basalts sourced mainly from recycled upper oceanic crust that is basalt-rich and contains little or no sediment.

The equation of state based on the Group Contribution – Polar Perturbed Chain – Statistical Associating Fluid Theory (GC-PPC-SAFT), which is PC-SAFT combined with the group contribution proposed by Tamouza et al., Fluid Phase Equilib. 2004; 222–223:67–76 and a polar term developed by NguyenHuynh et al., Fluid Phase Equilib . 2008; 264 (1–2):62–75, is employed here to model the solubility of hydrogen in oxygenated compounds mixtures such as alcohols, ethers, diols, aldehydes. Our analysis shows that in such systems, the gas solubility may be driven by available volume effects. For this reason, a modified version of this equation of state taking into account non-additive segment diameters, is used in this work. Systematic tests are performed on binary mixtures and a predictive scheme is proposed. A correlation based on the group contribution method is also suggested as a predictive way to determine the non-additive parameter (l ij ). Correlations and predictions are qualitatively and quantitatively satisfactory. The deviations are within the experimental uncertainty (∼10%).

International audience; Although metathesis photoinduced catalysis is now well established, there is little development in thin film preparation using photochemically activated ring-opening metathesis polymerization (ROMP). Herein, a N-heterocyclic carbene (NHC) photogenerator (1,3-bis(mesityl)imidazolium tetraphenylborate) is combined with an inactive metathesis catalyst ([RuCl2(p-cymene)]2) to generate under UV irradiation an active catalyst (p-cymene)RuCl2 (NHC), that is capable of producing in a single step cross-linked copolymer films by ROMP of norbornene with dicyclopentadiene. The study shows that the photoinitiated catalytic system can be optimized by increasing the yield of photogenerated NHC through a sensitizer (2-isopropylthioxanthone), and by choosing [RuI2(p-cymene)]2 as precatalyst to provide a long-term photolatency. The cross-linked polymer structure is investigated by a range of techniques including gel content measurement, FT-IR and solid-state 13C NMR spectroscopy, TGA and DSC, which reveal a cross-linking mechanism proceeding through both metathesis and olefin coupling.

Along with coral reefs and mangroves, seagrass meadows are being threatened globally Southeast Asia is considered within the area of seagrasses’ cradle of diversity. However, information on the current status of seagrass beds from Southern Viet Nam is limited due to lack of reliable data about seagrass species occurring in the Southeast Asian region. One factor is the difficulty of unambiguous species identification. For example, the leaf morphological characteristics of Halophila ovalis and closely related species are overlapping which leads to misidentifications. In this study, the latest satellite Landsat 8 OLI and SENTINEL-2B image analyses were applied to determine the distribution of seagrass beds in Southern Viet Nam. Detailed morphological and genetic marker analyses were used to determine and update the species composition. The present study together with literature reviews indicate that the total area of seagrass beds from Southern Viet Nam are 10,832.1 ha. 2562 ha (or 19.1%) of seagrass coverage has been lost. The seagrass beds at Phu Quoc Island are the largest with 7579 ha. The occurrence of Halophila major is updated for almost all off-shore islands and open-water areas.

This study clarifies the reaction pathway for biomass pyrolysis to phenolic compounds and aromatic hydrocarbons by analyzing 20 biomass samples using a central composite design and response surface plot. The pyrolysis reaction was performed using two integrated fixed-bed reactors. The product yield was significantly affected by pyrolysis temperature when utilizing the thermal cracking, repolymerization, and Boudouard reaction pathways. The bio-oil used in the study was obtained from the volatile matter fraction, where the fixed carbon content strongly affected biochar yield. Regarding bio-oil composition, both pyrolysis temperature and biomass constituents, including hemicellulose and lignin, significantly affected the yield of phenolics and aromatic hydrocarbons. In addition, biomass pyrolysis reaction pathways toward phenolic compounds and aromatic hydrocarbons were proposed.

The strong temporal backscatter signature of rice growing above the water's surface allows for the use of synthetic aperture radar (SAR) for paddy rice crop mapping in Southern Vietnam (Mekong Delta). In Northern Vietnam (Red River Delta), rice mapping using SAR is a challenge and is rarely performed because of the complex land-use/land-cover. Nevertheless, information about rice fields is needed for hydrological simulations in river basins such as the Cau River basin. The objective of this research is to investigate the potential of RADARSAT-2 band- C in identifying rice fields over a large and fragmented land-use area. Two methods are proposed, one for each data type, adapted to the land-use/land-cover of the study area. The thresholding technique, with a statistical analysis of the temporal variation of rice backscattering, was applied to the HH like-polarized ratio of dual-pol data. The support vector machine (SVM) algorithm was applied to the full quad-pol and a single HH-polarization calculated from polarimetric data. This study demonstrates that RADARSAT-2 dual- and quad-pol data can be successfully used to identify cultivated rice fields. However, the dual-pol data seems less efficient than the quad-pol data and the SVM classification is more flexible than the thresholding technique. Between the full quad-pol and a single polarization, the overall classification accuracy shows that the results derived from the single HH polarization are 3 to 10% less accurate than those derived from the classification of full quad-pol data. The results show the usefulness of polarimetric C -band data for the identification of rice fields in Northern Vietnam.

We report a method to generate the N-heterocyclic carbene (NHC) 1,3-dimesitylimidazol-2-ylidene (IMes) under UV-irradiation at 365 nm to characterize IMes and determine the corresponding photochemical mechanism. Then, we describe a protocol to perform ring-opening metathesis polymerization (ROMP) in solution and in miniemulsion using this NHC-photogenerating system. To photogenerate IMes, a system comprising 2-isopropylthioxanthone (ITX) as the sensitizer and 1,3-dimesitylimidazolium tetraphenylborate (IMesH+BPh4-) as the protected form of NHC is employed. IMesH+BPh4- can be obtained in a single step by anion exchange between 1,3-dimesitylimidazolium chloride and sodium tetraphenylborate. A real-time steady-state photolysis setup is described, which hints that the photochemical reaction proceeds in two consecutive steps: 1) ITX triplet is photo-reduced by the borate anion and 2) subsequent proton transfer takes place from the imidazolium cation to produce the expected NHC IMes. Two separate characterization protocols are implemented. Firstly, CS2 is added to the reaction media to evidence the photogeneration of NHC through formation of the IMes-CS2 adduct. Secondly, the amount of NHC released in situ is quantified using acid-base titration. The use of this NHC photo-generating system for the ROMP of norbornene is also discussed. In solution, a photopolymerization experiment is conducted by mixing ITX, IMesH+BPh4-, [RuCl2(p-cymene)]2 and norbornene in CH2Cl2, then irradiating the solution in a UV reactor. In a dispersed medium, a monomer miniemulsion is first formed then irradiated inside an annular reactor to produce a stable poly(norbornene) latex.

The aim of this study was to determine the effect of soil amendments on P pools and their depletion by plants and microbes. The experiment was divided into two parts. In Part A, barley straw (C/P 255) was added alone or with inorganic P to reduce the C/P ratio to 127 or 25 (straw treatments). In three other treatments, the same amount of P was added as in the straw treatments as inorganic P (fertilizer treatments). The soil was incubated for three weeks. Then (Part B), wheat was grown for five weeks in one set of soils. Barley straw was added to another set to increase microbial growth and incubated moist for three weeks. P pools were measured at the end of Part A and Part B. At the end of Part A all P pools increased with P addition rate. P pools were greater in the fertilizer than the straw treatments except for microbial biomass P (MBP) which was greater in the straw treatments. After wheat growth, HCl-P, phosphatase-P, citrate-P, CaCl2-P were depleted compared to Part A, MBP was higher. Addition of barley straw in Part B induced depletion of HCl-P, and citrate-P, but increased phosphatase-P, CaCl2-P and MBP. It is concluded that the size of the P pools is mainly influenced by P addition rate not form in which P is added. The impact of growing plants on P pools differs from that of microbes stimulated by high C/P straw addition.

International audience; 1,3-Bis(mesityl)imidazolium tetraphenylborate (IMesH+ BPh4−) can be synthesized in one step by anion metathesis between the corresponding imidazolium chloride and sodium tetraphenylborate. In the presence of 2-isopropylthioxanthone (sensitizer), an IMes N-heterocyclic carbene (NHC) ligand can be photogenerated under irradiation at 365 nm through coupled electron/proton transfer reactions. By combining this tandem NHC photogenerator system with metathesis inactive [RuCl2(p-cymene)]2 precatalyst, the highly active RuCl2(p-cymene)(IMes) complex can be formed in situ, enabling a complete ring-opening metathesis polymerization (ROMP) of norbornene in the matter of minutes at room temperature. To the best of our knowledge, this is the first example of a photogenerated NHC. Its exploitation in photoROMP has resulted in a simplified process compared to current photocatalysts, because only stable commercial or easily synthesized reagents are required.

International audience; This work consists of the adaptation of a non-additive hard sphere theory inspired by Malakhov and Volkov, Polym. Sci. Ser. A. 2007;49(6):745-756 to a square-well chain. Using the thermodynamic perturbation theory, an additional term is proposed that describes the effect of perturbing the chain of square well spheres by a non-additive parameter. In order to validate this development, NPT Monte Carlo simulations of thermodynamic and structural properties of the non-additive square well (NASW) for a pure chain and a binary mixture of chains are performed. Good agreements are observed between the compressibility factor originating from the theory and those from molecular simulations.