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In this study, a novel superabsorbent polymer tapioca starch-g-poly(acrylic acid-2-acrylamido-2-methylpropane sulfonic acid)/ammonium polyphosphate (TS-g-AA-AMPS/APP) was synthesized based on the graft copolymerization of tapioca starch (TS) with acrylic acid (AA) and 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) via free radical polymerization in aqueous solution with ammonium polyphosphate (APP) additive added for study. The synthesized superabsorbent polymer material was characterized by Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FE-SEM), energy-dispersive x-ray spectroscopy (EDS), and thermogravimetric analysis (TGA). Research investigating the material synthesis conditions to absorbance in distilled water and 0.9 wt% NaCl solution has also been studied. Under optimal synthesis conditions, the absorbance in distilled water and 0.9 wt% NaCl solution were 416 g g ^−1 and 61 g g ^−1 , respectively, for the sample with 3 wt% APP content. The introduction of APP units has improved the absorption properties of the material such as the water retention capacity reaching 55.25% in 10 h at 60 °C. TS-AA-AMPS/APP exhibits reversible swelling ability, with the swelling level not being reduced compared to the initial after 5 swelling-drying cycles at 60 °C, and water absorption reaches swelling equilibrium after about 270 min. Additionally, TGA thermogravimetric analysis results showed an improvement in the thermal stability of TS-AA-AMPS/APP compared to the pure polymer. These results show that the TS-AA-AMPS/APP polymer with excellent swelling properties, low production cost, and environmentally friendly has the potential for practical applications in agriculture, gardening, and water retention materials.

An unsymmetrical salen-type Schiff base ligand, (Z)-1-(((2-((E)-(2-hydroxy-6-methoxybenzylidene)amino)phenyl)amino)methylene)naphthalen-2(1H)-one, and its Zn(II), Cu(II), Co(II), Mn(II), and Fe(III) complexes were synthesized and characterized by mass (MS), nuclear magnetic resonance (NMR), infrared (IR), ultraviolet-visible (UV-Vis) spectra, and effective magnetic moments. The thermal analyses of the obtained ligand and metal complexes were conducted by thermogravimetric analysis (TGA). Antimicrobial activity of the unsymmetrical Schiff base ligand and its metal complexes were examined for Staphylococcus aureus as Gram-positive bacteria and Escherichia coli as Gram-negative bacteria. In vitro anticancer property of synthetic compounds was estimated against human cancer cell lines, a subline of Hela tumor cell line (KB), and a human liver cancer cell line (HepG-2) as well.

Cultivation of microalgae in wastewaters and co-production of algal biomass have been considered as a sustainable approach for wastewater treatment. To achieve desirable biomass productivity and pollutants removal efficiencies, microalgal strain, cultivation mode and culturing conditions should be optimized. This was firstly aimed at examining growth characteristics of Chlorella variabilis TH03 strain under phototrophic, heterotrophic and mixtrophic cultivations using BG-11 medium as the sole of nutrient source. Secondly, the culturing variables such as aeration rate, percent dilution, N/P ratio and supplemented CO2 concentration were optimized to maximize biomass production and nutrient removal efficiencies of the algal strain in domestic wastewater. Thirdly, growth and nutrient removal capability of C. variabilis TH03 were investigated in an outdoor reactor system using domestic wastewater as a culture medium. Data showed that C. variabilis TH03 grew well under phototrophic and mixtrophic conditions but completely inhibited under heterotrophic conditions. In mixtrophic conditions, optimal aeration rate, percent dilution, N/P ratio and supplemented CO2 concentration achieved for the maximum growth and nutrient removal efficiencies were 0.2 vvm, no dilution, N/P = 15:1 and 15% CO2, respectively. Moreover, C. variabilis TH03 also exhibited an outstanding growth and nutrient removal capability in the outdoor reactor system, reaching areal biomass productivity of 39.5 g/m2∙day. Pollutants including COD, TN and TP were removed at efficiencies of 73.9, 97.1 and 99.8%, respectively. Nutrient levels in the effluent dropped below those required by the national technical regulation on domestic wastewater QCVN 14:2008/BTNM and QCVN 14-MT: 2015/BTNMT. The obtained results are useful for further study in large scale cultivation of C. variabilis TH03 for the production of high volume and low price biomass, helping to obtain returns from treatment of the waste stream, which is currently considered as a major source of water pollution in Vietnam.

In this study, cuprous(I) oxide nanoparticles (Cu _2 ONPs) and APP@PEI (polyethyleneimine-modified ammonium polyphosphate) materials were successfully synthesized and combined to create a flame-retardant system for the fabrication of epoxy (EP) resin with high flame resistance. The characteristic results revealed that the synthesized Cu _2 ONPs exhibited a particle shape with a size below 200 nm. The synthesized APP@PEI material possessed dimensions ranging from 10–20 micrometers, featuring a core–shell structure. The combination of Cu _2 ONPs and APP@PEI has proven to be an effective flame-retardant system, significantly enhancing the flame resistance of EP resin. The epoxy-based composite prepared with 2 wt% Cu _2 ONPs and 18 wt% APP@PEI demonstrated high flame resistance, achieving a V-0 rating (the highest rating according to the UL-94 method for evaluating the flame retardancy of materials) and a limiting oxygen index value of 36% (indicating the material’s self-extinguishing ability). This limiting oxygen index value was significantly higher than that of neat EP resin, which only reached 19%. The characteristic results of the flame-retardant epoxy-based composite demonstrated that both APP@PEI and Cu _2 ONPs were well dispersed in the EP resin and did not undergo structural transformation during the material preparation process. APP@PEI and Cu _2 ONPs enhanced the thermal degradation of EP-based composite materials at lower temperatures, exhibiting a faster degradation rate compared to EP resin. This augmentation facilitates the formation of a protective char layer on the surface of composite, thereby shielding it from direct flame exposure during combustion. Cu _2 ONPs played a role as oxidative catalysts, acting as Lewis acids. In addition to enhancing fire resistance, APP@PEI and Cu _2 ONPs have increased thermal conductivity, reduced impact strength, maintained tensile strength, and improved flexural strength of the composite material based on EP compared to neat EP resin.

Bis(3-indolyl)methanes (BIM) are highly valuable and appear in the core structure of many natural products and pharmacologically active compounds (anticancer, anti-inflammatory, antiobesity, antimetastatic, antimicrobial, etc.). Herein, we have disclosed an air stable and highly efficient CuFe2O4 heterogeneous catalyst for alkylation of indoles with alcohols to give bis(3-indolyl)methanes in very good yields. The CuFe2O4 catalyst has been found to be magnetically recycled at least five times without losing significant catalytic activity.

Unsymmetrical tetradentate Schiff base Fe(III) and Cu(II) complexes were prepared by the coordination of some unsymmetrical tetradentate Schiff base ligands with CuCl2·2H2O or FeCl3·6H2O. The obtained complexes were characterized by ESI-MS, IR, and UV-Vis. The spectroscopic data with typical signals are in agreement with the suggested molecular formulae of the complexes. Their cyclic voltammetric studies in acetonitrile solutions showed that the Cu(II)/Cu(I) and Fe(III)/Fe(II) reduction processes are at (−)1.882–(−) 1.782 V and at (−) 1.317–(−) 1.164 V, respectively. The in vitro cytotoxicity of obtained complexes was screened for KB and Hep-G2 human cancer cell lines. The results showed that almost unsymmetrical tetradentate Schiff base complexes have good cytotoxicity. The synthetic complexes bearing the unsymmetrical tetradentate Schiff base ligands with different substituted groups in the salicyl ring indicate different cytotoxicity. The obtained Fe(III) complexes are more cytotoxic than Cu(II) complexes and relative unsymmetric Schiff base ligands.

A series of platinum(II) complexes with chiral Schiff base ligands derived from various salicylaldehydes with (R,R′)- and (S,S′)-cyclohexanediamine were synthesized and characterized by ESI-MS, IR, and NMR. Obtained spectra with typical signals were in agreement with suggested molecular formulae of the complexes. Their photophysical properties were studied by UV-visible and emission spectroscopies. The UV-Vis showed the typical band with low energy at visible range 400–500 nm for MLCT, and this band can emit the luminescent band with emission maximum wavelengths at 529–595 nm. The in vitro cytotoxicity of obtained platinum(II) complexes was screened for KB and MCF-7 human cancer cell lines. The results showed that (S)-enantiomers were more active than (R)-enantiomers and the different positions of methoxy group in salicyl ring gave different cytotoxicities.

The title compound, C24H29NO4, is the product of a Petrenko–Kritchenko condensation of 1,5-bis(2-formylphenoxy)-3-oxapentane, pentan-3-one and methylammonium acetate in ethanol. The molecule has mirror symmetry. The aza-14-crown-3 ether ring adopts a bowl conformation stabilized by a weak intramolecular C—H...O hydrogen bond. The conformation of the C—O—C—C—O—C—C—O—C polyether chain is t–g+–t–t–g−–t (t = trans, 180°; g = gauche, ±60°). The dihedral angle between the benzene rings fused to the aza-14-crown-4-ether moiety is 72.68 (4)°. The piperidinone ring adopts a chair conformation. The nitrogen atom has a trigonal–pyramidal geometry, the sum of the bond angles being 335.9°. In the crystal, the molecules are linked by weak C—H...O interactions, forming zigzag chains propagating along the [100] direction.

The title compound, C20H24N2O4, is the product of a ring-expansion reaction from a seven-membered hexahydroazepine to a nine-membered azonine. The azonine ring of the molecule adopts a chair–boat conformation. In the crystal, molecules are linked by bifurcated N—H...(O,O) hydrogen bonds, generating [010] zigzag chains. The title compound shows inhibitory activity against acetylcholinesterase and butyrylcholinesterase, and might be considered as a candidate for the design of new types of anti-Alzheimer's drugs.

1-(p-Methoxyphenyl)tetrazolyl-substituted 6,7-dimethoxy(6,7-methylenedioxy)-1,2,3,4-tetrahydroisoquinolines formed tetrazolyl-substituted azocines in high yields by using activated alkynes. Unsubstituted at 6,7,8-aromatic fragment 1-tetrazolylisoquinoline interacted in several pathways forming tetrazolyl-substituted azocines, 1-tetrazolyl-1-R-vinylisoquinolines and 3-azaspiro[5.5]undeca-1,7,9-triene.

In this paper, we study optimality conditions as well as sensitivity analysis of parametric convex minimax programming problems. The main tools used here are the formulas for computing the subdifferentials of maximum functions under some suitable regularity conditions. More precisely, we use these tools to study optimality conditions for the problem under consideration. These results are then applied to obtain optimality conditions for multiobjective optimization problems, which constitute the first part of the paper. In the second part, we derive formulas for computing the subdifferential in the sense of convex analysis and singular subdifferential of the optimal value function for the problem in question. [ABSTRACT FROM AUTHOR]