gel permeation
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Polymers ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 285
Author(s):  
Yulia S. Dyuzhikova ◽  
Anton A. Anisimov ◽  
Alexander S. Peregudov ◽  
Mikhail I. Buzin ◽  
Galina G. Nikiforova ◽  
...  

New non-crystallizable low-dispersity star-shaped polydimethylsiloxanes (PDMS) containing stereoregular cis-tetra(organo)(dimethylsiloxy)cyclotetrasiloxanes containing methyl-, tolyl- and phenyl-substituents at silicon atoms and the mixture of four stereoisomers of tetra[phenyl(dimethylsiloxy)]cyclotetrasiloxane as the cores were synthesized. Their thermal and viscous properties were studied. All synthesized compounds were characterized by a complex of physicochemical analysis methods: nuclear magnetic resonance (NMR), FT-IR spectroscopy, gel permeation chromatography (GPC), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), viscometry in solution, rheometry, and Langmuir trough study.


Molecules ◽  
2022 ◽  
Vol 27 (1) ◽  
pp. 266
Author(s):  
Valentina S. Borovkova ◽  
Yuriy N. Malyar ◽  
Irina G. Sudakova ◽  
Anna I. Chudina ◽  
Andrey M. Skripnikov ◽  
...  

Spruce (Piceaabies) wood hemicelluloses have been obtained by the noncatalytic and catalytic oxidative delignification in the acetic acid-water-hydrogen peroxide medium in a processing time of 3–4 h and temperatures of 90–100 °C. In the catalytic process, the H2SO4, MnSO4, TiO2, and (NH4)6Mo7O24 catalysts have been used. A polysaccharide yield of up to 11.7 wt% has been found. The hemicellulose composition and structure have been studied by a complex of physicochemical methods, including gas and gel permeation chromatography, Fourier-transform infrared spectroscopy, and thermogravimetric analysis. The galactose:mannose:glucose:arabinose:xylose monomeric units in a ratio of 5:3:2:1:1 have been identified in the hemicelluloses by gas chromatography. Using gel permeation chromatography, the weight average molar mass Mw of hemicelluloses has been found to attain 47,654 g/mol in noncatalytic delignification and up to 42,793 g/mol in catalytic delignification. Based on the same technique, a method for determining the α and k parameters of the Mark–Kuhn–Houwink equation for hemicelluloses has been developed; it has been established that these parameters change between 0.33–1.01 and 1.57–472.17, respectively, depending on the catalyst concentration and process temperature and time. Moreover, the FTIR spectra of the hemicellulose samples contain all the bands characteristic of heteropolysaccharides, specifically, 1069 cm−1 (C–O–C and C–O–H), 1738 cm−1 (ester C=O), 1375 cm−1 (–C–CH3), 1243 cm−1 (–C–O–), etc. It has been determined by the thermogravimetric analysis that the hemicelluloses isolated from spruce wood are resistant to heating to temperatures of up to ~100 °C and, upon further heating, start destructing at an increasing rate. The antioxidant activity of the hemicelluloses has been examined using the compounds simulating the 2,2-diphenyl-2-picrylhydrazyl free radicals.


Foods ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 3137
Author(s):  
Roberto Cabizza ◽  
Francesco Fancello ◽  
Giacomo Luigi Petretto ◽  
Roberta Addis ◽  
Salvatore Pisanu ◽  
...  

The aim of this work was to valorize the by-product derived from the ricotta cheese process (scotta). In this study, ovine scotta was concentrated by ultrafiltration and then subjected to enzymatic hydrolyses using proteases of both vegetable (4% E:S, 4 h, 50 °C) and animal origin (4% E:S, 4 h, 40 °C). The DPP-IV inhibitory, antioxidant, and antibacterial activities of hydrolysates from bromelain (BSPH) and pancreatin (PSPH) were measured in vitro. Both the obtained hydrolysates showed a significantly higher DPP-IV inhibitory activity compared to the control. In particular, BSPH proved to be more effective than PSPH (IC50 8.5 ± 0.2 vs. 13 ± 1 mg mL−1). Moreover, BSPH showed the best antioxidant power, while PSPH was more able to produce low-MW peptides. BSPH and PSPH hydrolysates showed a variable but slightly inhibitory effect depending on the species or strain of bacteria tested. BSPH and PSPH samples were separated by gel permeation chromatography (GPC). LC-MS/MS analysis of selected GPC fractions allowed identification of differential peptides. Among the peptides 388 were more abundant in BSPH than in the CTRL groups, 667 were more abundant in the PSPH group compared to CTRL, and 97 and 75 of them contained sequences with a reported biological activity, respectively.


Polymers ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 4257
Author(s):  
Sol Lee Park ◽  
Jang Yeon Cho ◽  
Su Hyun Kim ◽  
Shashi Kant Bhatia ◽  
Ranjit Gurav ◽  
...  

Having the advantage of eco-friendly decomposition, bioplastics could be used to replace petroleum-based plastics. In particular, poly(3-hydroxybutyrate) (PHB) is one of the most commercialized bioplastics, however, necessitating the introduction of PHB-degrading bacteria for its effective disposal. In this study, Microbulbifer sp. SOL66 (94.18% 16S rRNA with similarity to Microbulbifer hydrolyticus) demonstrated the highest degradation activity among five newly screened Microbulbifer genus strains. Microbulbifer sp. SOL66 showed a rapid degradation yield, reaching 98% in 4 days, as monitored by laboratory scale, gas chromatography-mass spectrometry, scanning electron microscopy, gel permeation chromatography, and Fourier transform infrared spectroscopy. The PHB film was completely degraded within 7 days at 37 °C in the presence of 3% NaCl. When 1% xylose and 0.4% ammonium sulfate were added, the degradation activity increased by 17% and 24%, respectively. In addition, this strain showed biodegradability on pellets of poly(3-hydroxybutyrate-co-4-hydroxybutyrate), as confirmed by weight loss and physical property changes. We confirmed that Microbulbifer sp. SOL66 has a great ability to degrade PHB, and has rarely been reported to date.


2021 ◽  
Vol 11 ◽  
Author(s):  
Hui Jia ◽  
Bin Zhao ◽  
Fangfang Zhang ◽  
Ramesh Kumar Santhanam ◽  
Xinying Wang ◽  
...  

Polysaccharides are the main active ingredients of ginseng. To extract the most effective polysaccharides against hepatocellular carcinoma (HCC), we isolated and characterized the polysaccharides from the mountain cultivated ginseng (MCG) and compared their composition and cytotoxic effect with cultivated ginseng (CG) polysaccharide against HepG2 cell lines for the first time. MCG polysaccharides and CG polysaccharides were fractionated into two fractions such as MTPS-1, MTPS-2 and CTPS-1, CTPS-2 by salting out, respectively. Compared to CG, MCG possessed appreciable cytotoxic effect against HepG2 cells among that MTPS-1 possess fortified effect. Then, MTPS-1 was selected for further isolation process and seven acidic polysaccharides (MCGP-1–MCGP-7) were obtained using ethanol precipitation, ion-exchange, and gel permeation chromatography techniques. Structural characteristics of the polysaccharides (MCGP-1–MCGP-7) were done by adapting methylation/GC-MS and NMR analysis. Overall, MCGP-3 polysaccharide was found to possess significant cytotoxic effect against HepG2 cells with the IC50 value.


2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Anand K. Agrahari ◽  
Sunil Kumar ◽  
Anindra Sharma ◽  
Vinod K. Tiwari

High-sugar-tethered glycodendrimers are a remarkable tool in glycobiology for the investigation of carbohydrate-protein interaction using its multivalency property. An enthralling double-stage convergent synthetic approach was selected to build a novel class of chlorine-containing glucose-coated dendrimers using an efficient click catalyst ‘dinuclear copper(I) thiodiacetate complex.’ In this context, cyclen core was developed through a divergent approach, while the glucodendron was developed via a convergent approach independently. Both azide-alkyne partners were coupled through a modular copper azide-alkyne cycloaddition (CuAAC) strategy to afford a high yield of the desired 36-glucose-coated glycodendrimer. The synthesized glycodendrimer has been elucidated by NMR, gel permeation chromatography (GPC), and IR spectral analysis.


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