Synthesis of iron oxyhydroxide-coated rice straw (IOC-RS) and its application in arsenic(V) removal from water.

Because of the recognition that arsenic (As) at low concentrations in drinking water causes severe health effects, the technologies of As removal have become increasingly important. In this study, a simplified and effective method was used to immobilize iron oxyhydroxide onto a pretreated naturally occurring rice straw (RS). The modified RS adsorbent was characterized, using scanning electron microscope, Fourier transform infrared spectroscopy, thermogravimetric analyzer, and surface area analyzer. Experimental batch data of As(V) adsorption were modeled by the isotherms and kinetics models. Although all isotherms, the Langmuir model fitted the equilibrium data better than Freundlich and Dubinin-Radushkevich models and confirmed the surface homogeneity of adsorbent. The iron oxyhydroxide-coated rice straw (IOC-RS) was found to be effective for the removal of As(V) with 98.5% sorption efficiency at a concentration of <50 mg/L of As(V) solution, and thus maximum uptake capacity is ∼22 and 20 mg As(V)/g of IOC-RS at pH 4 and 6, respectively. The present study might provide new avenues to achieve the As concentrations required for drinking water recommended by the World Health Organization.

Flavonoid glycosides from Odontonema strictum leaves.

Odontonema strictum (Acanthaceae) leave extract was investigated for its flavonoid content. Column chromatography was used for compound isolation and mass spectrometry was performed using electrospray ionization (ESI) in the negative ion mode for compound identification. The full characterization of luteolin 7-O-[ß-D-apiofuranosyl-(1 â†’ 2)-O-ß-D-ribofuranoside], a flavone glycoside, was achieved using tandem mass spectrometry and high resolution 1D and 2D Nuclear Magnetic Resonance (NMR). Among the 10 flavonoids glycosides detected in the ethanol extract, beside the isolated one, 3 flavone glycosides with luteolin or apigenin aglycone were tentatively identified.

Targeting structural motifs of flavonoid diglycosides using collision-induced dissociation experiments on flavonoid/Pb2+ complexes.

Differentiation of flavonoid congeners remains a challenging analytical problem and confirming the structures of the different isomers is difficult, even when they can be adequately separated from mixtures. In the present report, in order to overcome the limits of our recently proposed method that relies on the distinctive CID behaviors of [(flavonoid - H(+)) + Cu(2+)] complexes to obtain direct structural evidences, we decided to investigate the possibility of using Pb(II) complexation to generate significant differences upon CID. We selected five flavonoid diglycosides with targeted structural features to estimate the applicability of this methodology. Electrospray ionization from methanol-not acetonitrile-solutions was advantageously used for preparing the [(flavonoid diglycoside - H(+)) + Pb(2)+](+) complexes. Upon collisional activation, [(flavonoid diglycoside- H(+)) + Pb(2+)](+) ions mainly dissociate by glycosidic bond cleavage. Nevertheless, specific cross-ring cleavages are also induced and lead to a clear-cut determination of (i) the nature of the disaccharide group, i.e. rutinose or neohesperidose, (ii) the nature of the aglycone part, flavanone or flavone and (iii) the relative position of the disaccharide substituent on the aglycone part, i.e. 3-O- vs 7-O positions.

Insufficient yet improving involvement of the global south in top sustainability science publications.

The creation of global research partnerships is critical to produce shared knowledge for the implementation of the UN 2030 Agenda for Sustainable Development. Sustainability science promotes the coproduction of inter- and transdisciplinary knowledge, with the expectation that studies will be carried out through groups and truly collaborative networks. As a consequence, sustainability research, in particular that published in high impact journals, should lead the way in terms of ethical partnership in scientific collaboration. Here, we examined this issue through a quantitative analysis of the articles published in Nature Sustainability (300 papers by 2135 authors) and Nature (2994 papers by 46,817 authors) from January 2018 to February 2021. Focusing on these journals allowed us to test whether research published under the banner of sustainability science favoured a more equitable involvement of authors from countries belonging to different income categories, by using the journal Nature as a control. While the findings provide evidence of still insufficient involvement of Low-and-Low-Middle-Income-Countries (LLMICs) in Nature Sustainability publications, they also point to promising improvements in the involvement of such authors. Proportionally, there were 4.6 times more authors from LLMICs in Nature Sustainability than in Nature articles, and 68.8-100% of local Global South studies were conducted with host country scientists (reflecting the discouragement of parachute research practices), with local scientists participating in key research steps. We therefore provide evidence of the promising, yet still insufficient, involvement of low-income countries in top sustainability science publications and discuss ongoing initiatives to improve this.

Collision-induced dissociation of flavonoid 7-O-diglycoside cations: elucidation of important structural motifs by selection of the cationizing reaction.

Flavonoids are ubiquitous molecules in nature and are found in almost all plants, including fruits and vegetables. Although flavonoids are structurally similar, subtle differences in their structures lead to important changes in their biological activities. Over years, mass spectrometry has become an ideal tool for the characterization of those important molecules. In particular to overcome the challenge of structure assignment, tandem mass spectrometry was used in numerous studies. In the present study, we submitted selected flavonoid 7- O-diglycosides to electrospray ionization to prepare different kinds of flavonoid ions, i.e. protonated, sodium- cationized and copper-cationized molecules. Most of the investigated reactions are already described in the literature in several papers and the aim of the present study is to present concise and coherent relations between CID reactions, cationizing agents and flavonoid 7-O-diglycoside structures. Some insights in the reaction mechanisms and the role of the cationizing particles will also be attempted.

Conversion of natural aldehydes from Eucalyptus citriodora, Cymbopogon citratus, and Lippia multiflora into oximes: GC-MS and FT-IR analysis.

Three carbonyl-containing extracts of essential oils from Eucalyptus citriodora (Myrtaceae), Cymbopogon citratus (Gramineae) and Lippia multiflora (Verbenaceae) were used for the preparation of oximes. The reaction mixtures were analyzed by GC-MS and different compounds were identified on the basis of their retention times and mass spectra. We observed quantitative conversion of aldehydes to their corresponding oximes with a purity of 95 to 99%. E and Z stereoisomers of the oximes were obtained and separated by GC-MS. During GC analysis, the high temperature in the injector was shown to cause partial dehydratation of oximes and the resulting nitriles were readily identified. Based on FT-IR spectroscopy, that revealed the high stability and low volatility of these compounds, the so-obtained oximes could be useful for future biological studies.

Mass spectra of 1,3,5-triarylpentane-1, 5-diones: formation and decomposition of pyrilium cation from the molecular ion.

Electron impact mass spectra of 1,3,5-triarylpentane-1,5-diones are reported. All compounds studied show a tendency to eliminate a water molecule and also the elements of [H3O] before fragmentation to smaller ions. The [H3O] loss proceeds via loss of water to form a pyran ion, which subsequently eliminates a hydrogen atom to form the stable pyrillium cation.