Proton Nuclear Resonance Spectroscopy Research Articles

Influence of secretome obtained from preovulatory follicular fluid on energy metabolism and meiotic competence of equine cumulus–oocyte complexes

Secretome is composed by proteins and microvesicles secreted by the granulosa cells that line the follicular wall. These bioactive compounds promote follicular growth and oocyte maturation, influencing oocyte metabolism. Hence, we hypothesized that addition of secretome from preovulatory follicular fluid (FF) to maturation medium may influence the meiotic competence and metabolism of cumulus-oocyte-complexes (COCs) obtained post mortem. FF was retrieved from preovulatory follicles (2 mares) after 32h of hCG administration. Three ml of FF from both mares were pooled, diluted 1:1 in PBS and centrifuged (4000g, 1h at 4°C) using a 10K Amicon® Ultra-15 Centrifugal Filter Unit and protein concentration was measured. A total of 186 COCs were retrieved from post mortem ovaries and were subjected to in vitro maturation (IVM) in TCM-199 medium, 10% of FBS and 5 mU/ml of FSH (Control; 59 oocytes) or with 20 µg/ml of secretome (Secretome20; 66 oocytes) or with 40 µg/ml of secretome (Secretome40; 61 oocytes) for 28 h in 5% CO2/95% air at 38.2°C. Oocytes were denuded, fixed in 4% formaldehyde and stained with Hoechst 33342 to assess chromatin conformation by fluorescence microscopy. Also, selected metabolites of the maturation medium prior to andafter IVM were assessed by magnetic proton nuclear resonance spectroscopy. After IVM, a trend towards glucose consumption and pyruvic acid production was observed compared to their controls prior IVM; a significant increase in lactic acid production in all treatments was observed (Table 1; p < 0.05). Our results show a tendency for quicker meiosis resumption in COCs incubated with Secretome40 (Table 2). In conclusion, secretome obtained from preovulatory follicular fluid added during IVM does not change COCs’ energy metabolism nor maturation rate of equine cumulus-oocyte complexes in our in vitro culture system. Funding: MCCIN/AEI (PID2020-112723RB-I00; RYC-2017-21545; RYC2020-028915-I), Junta de Extremadura-FEDER (IB20005).

Synthesis and Characterization of Biodegradable Jatropha Oil Based Polyurethanes Using Modified Sesame Oil as Cross-Linker Containing Different NCO Groups with Improved Thermal Stability

In this work, the modified S-diol were prepared from sesame oil to produce polyol. The thermal responsive vegetable oil-based polyurethane was prepared by polycondensation method. The different diisocyanate react with jatropha-sesame oil polyol to produce higher density with molecular weight of polyurethanes structure and functionality were characterized by Fourier transform spectroscopy, proton nuclear resonance spectroscopy and gel permeation chromatography. The thermal analysis was carried with TG analysis. The kinetic and thermodynamic parameters was calculated by TGA decomposition temperature and compared with PU-1, PU-2 and PU-3. Furthermore, the corresponding decomposition temperature of polyurethanes activation energy were calculated by Coats-Redfern, Sharp-Wentworth and Freeman-Carols methods, and it is investigated with lifetime of polyurethanes. Depending on the physically observed NH and C=O linkages of polyurethane matrix, which enhancing the hard and soft segment to improve their chain mobility. The success of the investigated polyurethanes, the corresponding estimated enthalpy, entropy and pre-exponential factors are much closer with toluene and phenyl based polyurethane matrix

Synthesis and characterization of bio-polyurethanes prepared using certain bio-based polyols

Vegetable oils are considered to have huge potential as materials that can be used in the synthesis of high quality products such as, polyurethanes and poly (ether urethanes) etc. A series of bio-based triglyceride vegetable oils such as Azadirachta indica (neem oil), Jatropha curcas (jatropha oil) are used to prepare high molecular weight polyurethanes (PU’s). These are prepared by reactions involving polyols synthesized from neem and jatropha oil using aromatic diisocyanate. The cross-linking of the polyol and polyurethane structures is characterized by Fourier Transform Spectroscopy (FT-IR), Proton Nuclear Resonance Spectroscopy (1H NMR) and 13C Nuclear Resonance Spectroscopy (13C NMR). The effect of cross-linking on the polyols and chain extender density of polyurethane (PUs) molecular weight is determined by the Gel Permeation Chromatography (GPC). The power law model is used to calcuate the viscosity of the polyols characterized by Rheometry and flow rate of the polyols. The incorporation of the chain extender toluene diisocyanate (TDI) in polyurethane significantly improves the thermal properties along with the different weight loss in various temperature were characterized by thermogravimetry analysis (TGA). The thermal degradation and kinetic parameters such as entropy change, free energy change, apparent activation energy can be calculated using the Freeman-Carolls method to study the biodegradability of the polyurethanes(PUs).

Synthesis of O-carboxylated low molecular chitosan with azido phenyl group: Its application for adhesion prevention

A water-soluble photo-reactive chitosan derivative was synthesized as a novel anti-adhesive agent by combining low molecular O-carboxymethyl chitosan and photo-reactive N-(4-azidobenzoyloxy) succinimide. Photoreactive low molecular O-carboxymethyl chitosan was analyzed by Fourier transform infrared spectroscopy (FTIR) and proton nuclear resonance spectroscopy (1H NMR). Photo-immobilization of the polymer was confirmed using photo-mask and the degree of cross-linking was measured from the immobilized dried weight. The cytotoxicity of the photo-reactive low molecular O-carboxymethyl chitosan was confirmed by a MTT assay. In vivo animal study was performed to identify the synthetic material for antiadhesive effect. Furthermore, the protein release test that was performed to apply it as a drug-eluting anti-adhesive agent after bovine serum albumin (BSA), was immobilized to the photoreactive polymer. Because photo-reactive low molecular O-carboxymethyl chitosan has high water solubility as well as non-cytotoxicity and photoimmobilization, it may a suitable material for making drug-eluting antiadhesive agents.

Online coupling of enantioselective capillary gas chromatography with proton nuclear magnetic resonance spectroscopy

The hyphenation of enantioselective capillary gas chromatography and mass spectrometry is not always sufficient to distinguish between structural isomers, thus requiring peak identification by NMR spectroscopy. Here the first online coupling of enantioselective capillary gas chromatography with proton nuclear resonance spectroscopy is described for the unfunctionalized chiral alkane 2,4-dimethylhexane resolved on octakis(6-O-methyl-2,3-di-O-pentyl)-gamma-cyclodextrin at 60 degrees C. NMR allows constitutional and configurational isomers (diastereomers and enantiomers) to be distinguished. Enantiomers display identical spectra at different retention times, which enable an indirect identification of these unfunctionalized alkanes. The presented method is still at an early development stage, and will require instrumental optimization in the future.

Zinc tetranitrophthalocyanine: isomer separation and photophysical photobiological evaluation in J774A tumor cells

The synthesis of zinc tetranitrophthalocyanine ( T 4 NO 2 ZnPc ) was carried out and two structural isomers ( C 2v and C s) were separated by column chromatography and characterized by 400 MHz proton nuclear resonance spectroscopy and absorption spectroscopy. The photophysical and photobiological parameters for isomers C 2v and C s were determined in solution and in the presence of macrophage cell culture (J774A). The results obtained clearly indicated that the photophysical, photochemical and photobiological properties of the two isomers were different and each isomer showed a different biological behavior.

A 1H-NMR study of the solution conformation of Icaria chemotactic peptide and its [Lys 7] analog: Effects on the physiological activity of a substitution of proline to lysine at position 7

Solution conformations of Icaria chemotactic peptide isolated from the Ropalidian wasp venom and its [Lys 7] analog have been analyzed by the use of two-dimensional proton nuclear resonance spectroscopy. It has been shown that Icaria chemotactic peptide takes α helical conformation in the C-terminal 8–13 segment with the N-terminal 1–7 segment disordered. By contrast, the [Lys 7] analog takes α helical conformation over a wider range from residues 3 to 13. The present results indicate that the substitution of proline to lysine at position 7 results in a drastic change in solution conformation, providing the Icaria chemotactic peptide with new physiological functions.

Ignition quality determination of diesel fuels from hydrogen type distribution of hydrocarbons

Hydrogen types of diesellike hydrocarbon fuels which have dominant effect on the ignition quality have been identified. A scheme of characterizing the chemistry of hydrocarbon fuels in terms of these hydrogen types using proton nuclear resonance spectrometry has been proposed. Using this analysis technique on 70 different diesel fuels, whose cetane numbers were determined on a number of standard cetane rating engines, an empirical expression which relates the ignition quality to the hydrogen type distribution of the fuels has been developed. The developed expression and the relationship between the ignition delay and cetane number imply that the effective activation energy term in the usual semiempirical ignition delay expression is not a constant for a given fuel but is a function of pressure and temperature as well as the fuel chemistry.