Together we are strong: A new, robust method allows the measurement of residual chemical shift anisotropies for the determination of conformation and configuration of molecules in organic solvents. ...The power of the method is shown by the example of estrone and 13‐epi‐estrone (see structures), where only the combined use of residual chemical shift anisotropies and residual dipolar couplings leads to the distinction of the two diastereomers.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Tree-exuded gums are natural polymers that represent an abundant raw material in the food and pharmaceutical industries. The cashew gum can be obtained by exudation of trees of the genus Anacardium, ...a native species of the Brazilian northeast; its polymer consists of monosaccharide units propitious to the action of chemical reactions that tend to improve their intrinsic characteristics among them, as the degree of hydro-solubility. The objective of this work was to modify the exudate gum of Anacardium occidentale (cashew gum (CG)) through an amine reaction. The modification was confirmed by Nuclear Magnetic Resonance (1H NMR), infrared spectroscopy (FTIR), gel permeation chromatography (GPC), zeta potential, and thermogravimetric analysis (TG). In addition, the chemical modification altered the molar mass and surface charge of the CG, and the amino group binding to the CG polymers was confirmed by FTIR spectra. In addition, cytotoxicity tests were performed where cell viability was estimated by an MTT assay on RAW 264.7 macrophages. Through these tests, it was found that the amine caused an increase in the thermal stability of the amino compounds and did not present cytotoxic potential at concentrations below 50.0 mg/L.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Proton and deuterium NMR measurements are performed in Na-fluorhectorite powdered samples. The results are compared with NMR data from other 2:1 clays, and with the recent results of molecular ...simulations, they yield new information about the factors governing the geometry and dynamics of intercalated water in these materials. In the one-water layer regime, two different sites were identified, permitting us to elucidate the structure of interlamellar water. The role of proton exchange appears to be more pronounced in Na−Fht than in Na−vermiculite and is not limited to the 2WL regime. It appears to be promoted by a considerable amount of interlamellar water outside the hydration sphere of the cation.
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IJS, KILJ, NUK, PNG, UL, UM
•Two grafted graphene oxide were prepared by heating, in the presence of the radical initiator.•The grafting materials had different polarity and solubility characteristics.•Deuterium NMR ...spectroscopy evidenced lyotropic mesogenic behavior of the obtaining material.
Grafted derivatives of graphene oxide (GO), namely N-vinyl-2-pyrrolidone grafted-GO (GO-g-NVP) and oleic acid grafted-GO (GO-g-OLA) were prepared by heating GO in the presence of the corresponding vinyl monomers and the AIBN radical initiator. The lyotropic mesogenic behavior of GO-g-NVP and GO-g-OLA in DMSO‑d6 was proved by deuterium NMR spectroscopy, showing these materials could be used as alignment media for obtaining NMR anisotropic parameters in organic solvent.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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•Intermittent and continuous micro-aerations had similar overall performance.•Intermittent micro-aeration consumed 75% less oxygen than the continuous process.•Intermittent ...micro-aeration was able to remove acute toxicity completely.•Methanogenic inhibition by oxygen may divert more electrons to decolorization.
The effects of discontinuous micro-aeration on the biotransformation of the tetra-azo dye Direct Black 22 (DB22) and of its anaerobic by-products (aromatic amines) were tested using sequencing batch reactors. The experimental set-up consisted of three independent reactors (R1, R2, and R3) working with distinct cycles: R1 was completely anaerobic, while both R2 and R3 included a micro-aerated stage after an anaerobic stage (R2 continuously and R3 intermittently micro-aerated). Average DB22 removal efficiencies in R1, R2, and R3 were 81.4, 74.5 and 76.8%, respectively. R1 produced an effluent with high acute ecotoxicity (1.13% as effective concentration causing 50% of bioluminescence inhibition in Vibrio fischeri) due to aromatic amines accumulation. In contrast, no acute ecotoxicity was detected in the effluent of R2 and R3, reflecting aromatic amines removal. At the anaerobic stage of the cycle, R2 and R3 showed DB22 decolorization rates 73 and 123% higher than R1, respectively. At the same time, the corresponding values of estimated methane production were 35 and 37% lower. Thus, oxygen apparently changed the balance between methanogenesis and reductive decolorization, inhibiting the first process and enhancing the second.
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GEOZS, IJS, IMTLJ, IZUM, KILJ, KISLJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•Di-rhamnolipids can enhance the cellulosic conversion of the eucalyptus wastes.•Di-rhamnolipids can replace Triton X-100 as surfactant for enzymatic hydrolysis.•Use of di-rhamnolipids might ...eliminate the delignification step of eucalyptus chips.•Di-rhamnolipids might lead to economic benefits in 2 G ethanol production from eucalyptus wastes.
In this present work, rhamnolipids produced from Pseudomonas aeruginosa TGC07 were evaluated as biosurfactants for enzymatic hydrolysis of steam pretreated (not delignified) eucalyptus wastes comparatively to the synthetic surfactant Triton X-100. Enzymatic hydrolyses were performed at different substrate loadings (1%, 5% or 10% w/w) using commercial enzymes (Cellic® CTec1) at different dosages (14 or 28 FPU/gcellulose). The di-rhamnolipids were characterized by NMR spectroscopy. Cellulose conversions higher than 60% were achieved after 72 h runtime with the use of di-rhamnolipids at 5% solids, i.e., significantly superior to the conversions obtained from experiments performed without use of any surfactant, and similar to the performance of synthetic Triton X-100 at 5% solids. These results evidence that the use of natural renewable di-rhamnolipids as biosurfactants emerges as an interesting environmentally-friendly alternative to replace synthetic surfactant Triton X-100 as surfactant, aiming to increase production yields of cellulosic sugars by enhancing enzymatic hydrolysis of lignocellulosic biomasses such as steam pretreated eucalyptus wastes.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
An acrylonitrile/dimethylacrylamide cross-linked polymer could be swollen in different imidazolium ionic liquids. Mechanical compression of the obtained polymer gels inside an NMR tube allowed the ...measurement of residual dipolar couplings. Conformational analysis of the 1-methyl-3-butyl-imidazolium (BMIM) cation could be performed by including the measured RDCs as restraints in time-averaged molecular dynamics.
Swelling of an acrylonitrile/
N-N
-dimethylacrylamide copolymer in ionic liquids provides residual dipolar couplings which are applied to conformational analysis of the bulk ionic liquid.
In this work, antioxidant active films of poly (vinyl alcohol) – PVA incorporated with plant extract of Caesalpinia ferrea Martius (PF) were developed. The films were prepared through the solution ...casting technique. The concentrations of the plant extract used in the films were 0, 1 and 5% w/w. The analyses of phenolic and flavonoid content of the extracts resulted in 464.4 and 10.54 mgEQU/g, respectively. Antioxidant activity showed an index of 42.22 and 87.90% efficiency for free radical capture (DPPH) and total antioxidant capacity (TAC) techniques, respectively. Through the results of thermal analyses, a decrease in the degree of crystallinity and enthalpy of fusion were observed. An increase in thermal stability occurred after the incorporation of plant extract in the PVA matrix. For the mechanical test, an increase in tensile strength was noted. An increase was verified for water vapor permeability with the addition of plant extract. These films showed potentially antioxidant activities. It can be concluded that the incorporation of Caesalpinia ferrea Martius extract in the PVA had promising results, therefore, presenting an alternative for conventional passive packaging.
•Development of PVA films added with Caesalpinia ferrea Martius tree extract.•The plant extract showed good antioxidant activities.•The incorporation of plant extracts in the PVA films was indicated using FTIR.•Changes in the thermal and mechanical properties of PVA were observed.•The antioxidant activity remained considerable even after the addition in PVA.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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•Phthalated cashew gum was synthesized by the microwave-initiated method.•1H NMR spectroscopy was used to assess the degree of substitution of phthalated cashew gum.•Modified ...phthalated cashew gum nanoparticles were developed for delivery of benznidazole.
Chemical modification of polysaccharides is an important approach for their transformation into customized matrices that suit different applications. Microwave irradiation (MW) has been used to catalyze chemical reactions. This study developed a method of MW-initiated synthesis for the production of phthalated cashew gum (Phat-CG). The structural characteristics and physicochemical properties of the modified biopolymers were investigated by FTIR, GPC, 1H NMR, relaxometry, elemental analysis, thermal analysis, XRD, degree of substitution, and solubility. Phat-CG was used as a matrix for drug delivery systems using benznidazole (BNZ) as a model drug. BNZ is used in the pharmacotherapy of Chagas disease. The nanoparticles were characterized by size, PDI, zeta potential, AFM, and in vitro release. The nanoparticles had a size of 288.8 nm, PDI of 0.27, and zeta potential of –31.8 mV. The results showed that Phat-CG has interesting and promising properties as a new alternative for improving the treatment of Chagas disease.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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•Chemically cross-linked polyacrylonitrile (PAN) aligning media gels have been prepared.•Gels allow the measurement of RDCs and RCSAs using Gil's compression method.•Upon compression ...the gels present a deuterium splitting of more than 25 Hz.•The gels present a clean in background on the 1H-13C HSQC spectra.
Chemically cross-linked polyacrylontrile polymer gels, have been prepared as an alignment medium compatible with DMSO-d6. These gels allow measurement of residual dipolar couplings (RDCs) and residual chemical shift anisotropies (RCSAs) with good accuracy as tested with brucine and α-santonin natural compounds. The gels can be reversibly compressed allowing easy measurement of RCSAs. They also present good physical homogeneity, clean HSQC spectra with little background 1H signals, and allow unambiguous referencing of 13C spectra for RCSA extraction.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
