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Poly(ethylene glycol)-b-poly(lactic-co-glycolic acid) (PEG-PLGA) block copolymers and their thermoresponsive hydrogels have been widely studied as injectable depots for the sustained release of therapeutics. The thermogelling temperatures of PEG-PLGA copolymer solutions and the properties of their corresponding hydrogels are highly sensitive to the polymer microstructure. Often, it can be difficult to precisely control the microstructure because of transesterification side reactions that occur during ring-opening polymerisation (ROP) of lactide (L) and glycolide (G) monomers under various conditions. Therefore, we undertook a detailed study to understand how different reaction conditions influenced the reaction kinetics, monomer sequence and side reactions for the synthesis of a PLGA-PEG-PLGA triblock copolymer. ROP was conducted under thermal control (100, 110 and 120 degrees C) or in the presence of the catalysts tin(ii) 2-ethylhexanoate (Sn(Oct)(2)) and tin(ii) trifluoromethanesulfonate (Sn(OTf)(2)) at various catalyst loadings. The reactions were monitored via proton nuclear magnetic resonance (H-1 NMR) spectroscopy, gel permeation chromatography (GPC) and matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI ToF MS). While ROP proceeded faster with catalysts than the uncatalysed reaction at an equivalent temperature, the onset of side reactions typically occurred at much lower monomer conversions and to a greater extent, resulting in a plateau in the molecular weight and broadening of the molecular weight distribution. For Sn(Oct)(2) catalysed ROP, an increase in the catalyst loading had negligible effect on the occurrence or extent of side reactions, but led to a surprising increase in the rate of polymerisation of L relative to G. Sn(OTf)(2) catalysed ROP resulted in significant side reactions from the start of the polymerisation. These results provide insights into the influence of polymerisation conditions on the microstructure of PLGA-PEG-PLGA triblock copolymers that may prove useful for their improved and controlled synthesis. Refereed/Peer-reviewed

Deep eutectic solvents (DES) pretreatment is a promising approach to decrease “biomass recalcitrance” and boost the cellulose bioconversion as well as lignin valorization. In this study, a short-time DES pretreatment strategy was performed to enhance the production of high-yield fermentable sugars and tailored lignin nanoparticles (LNPs) from abaca. The glucose yield reached 92.4% under the optimal pretreatment condition (110 °C, 30 min), which was dramatically increased in comparison with that (9.5%) of control abaca. Simultaneously, nuclear magnetic resonance (NMR) and gel permeation chromatography (GPC) techniques indicated that the removed and regenerated DES lignin fractions displayed depolymerized structures and have relatively low molecular weight with relatively homogeneous morphology and narrow size distribution. Transmission electron microscope (TEM) analysis indicated that these lignin fractions are LNPs and the size of the optimal LNPs fraction is ranged from 30 nm to 50 nm. Moreover, all the DES lignin exhibited excellent antioxidant activities as compared to the commercial antioxidant butylated hydroxytoluene (BHT), which can be used as a promising natural antioxidant in industry. In short, this study demonstrated that the short-time DES pretreatment will improve the enzymatic digestibility and facilitate the controllable production and valorization of LNPs from abaca biomass, which will further promote the economic and overall benefits of biorefinery.

Yak yogurt, one of the naturally fermented dairy products prepared by local herdsmen in the Qinghai-Tibet Plateau, contains a diverse array of microorganisms. We isolated and identified a novel Streptococcus thermophilus strain, ZJUIDS-2-01, from the traditional yak yogurt. We further purified and carried out detailed structural, physiochemical, and bioactivity studies of an exopolysaccharide (EPS-3A) produced by S. thermophilus ZJUIDS-2-01. The weight-average molecular weight (Mw) of EPS-3A was estimated to be 1.38 × 106 Da by High-Performance Gel Permeation Chromatography (HPGPC). The monosaccharide analysis established its composition to be glucose, galactose, N-acetyl-D-galactosamine, and rhamnose in a ratio of 5.2:2.5:6.4:1.0. The molecular structure of EPS-3A was determined by the combination of permethylation analysis, FT-IR, and NMR spectroscopic techniques. The ζ-potential measurements indicated that EPS-3A had a pKa value of ~4.40. The DSC yielded a melting point (Tm) of 80.4 °C and enthalpy change (ΔH) of 578 J/g for EPS-3A, comparable to those of the xanthan gum (XG), a commercial EPS. EPS-3A exhibited better O/W emulsion stability and flocculating capacity than XG. Furthermore, it also demonstrated similar antioxidant activity to XG and promising in vitro antibacterial properties. This work evidenced that EPS-3A derived from S. thermophilus ZJUIDS-2-01 holds the potential for food and industrial applications.

Ten new carbohydrate-based aromatic polyurethanes have been synthesized using isomannide and/or a new 1,2,3-triazole isomannide derivative, IV, as the diol source in the polymerization reactions. As the isocyanate source, 1,4-phenylene diisocyanate or 2,4-toluene diisocyanate was used. To synthesize compound IV, isomannide was tosylated, the tosyl groups were substituted with azide, the triazole ring was formed by reaction with 2,4-pentane dione and finally carbonyl groups were converted into oximes. The synthesis of copolymers and terpolymers was performed using different proportions of diisocyanate and diol sources in DMF. The structural elucidation of the synthesized compounds and polymers was performed using spectroscopic techniques such as FTIR, 1D- and 2D-NMR and HRMS. The thermal behaviour and molecular weight distribution of polymers were analyzed by thermal gravimetric analysis and gel permeation chromatography, respectively. The surface properties of the polymers were analyzed using scanning electron microscopy. A comparative study on thermal behaviour of the synthesized polymers showed that polymers containing a higher amount of compound IV displayed better thermal stability. The average molecular weights of copolymers were observed to vary from 7,900 (PUR-3) to 21,000 (PUR-4) whereas for terpolymers, values of 19,000 (PUR-5), 5,100 (PUR-6), 22,000 (PUR-8) and 28,000 (PUR-9) were found. The diisocyanate source was found to have more effect on the surface properties of polymers than the diol source: when 2,4-toluene diisocyanate was used in polymer synthesis, the resultant polymers had a spongy morphology with cavities while a polymer matrix containing spheres and platelets was obtained when 1,4-toluene diisocyanate was used., Celal Bayar Universitesi [2016-060], The funding has been received from Celal Bayar Universitesi with Grant no. Research Projects Coordination Office Unit. Project Number: 2016-060.

INTRODUCTION This study investigated the role of natural polymers as moisturizers with low toxicity and biodegradability in the cosmetic and pharmaceutical industries. We isolated a polysaccharide extract from Dendrobium candidum (D. candidum) and determined its efficacy in skin hydration when used as an active cosmetic ingredient. METHODS The molecular weight distribution of D. candidum polysaccharides was analyzed via gel permeation chromatography (GPC). We performed real-time reverse transcription PCR (RT-PCR) and western blotting assays to investigate the physiological mechanism of the polysaccharides extracted from D. candidum (PDC). Based on in vitro data, the efficacy of PDC in improving skin condition was tested on the face of 21 volunteers. RESULTS The expression of filaggrin (FLG), caspase-14, and bleomycin hydrolase, which are the major components contributing to skin hydration, was significantly increased in the PDC-treated group. Further, the PDC upregulated the mRNA expression of occludin and claudin-1, which play a key role in epidermal barrier function. In addition, a topical application of PDC markedly increased skin hydration and improved trans-epidermal water loss (TEWL) and skin elasticity after 2 weeks. CONCLUSIONS It is the first study reporting the efficacy of PDC-mediated FLG mechanism associated with positive skin hydration. PDC can be used as an active ingredient in moisturizers. Long-term application of PDC-based moisturizers may result in significant improvement in elasticity and barrier function.

This study investigated the structural elucidation, anti-radical and immunomodulatory activities of polysaccharides from the roots of Glehnia littoralis. A crude polysaccharide was extracted from the roots of G. littoralis through the ultrasonic-assisted extraction and further purified by DEAE-52 cellulose and Sephadex G-100 gel column, a major polysaccharide fraction named GLP80-1 was obtained. The chemical properties and structure of GLP and GLP80-1 were characterized by acid hydrolysis, methylation analysis, along with high performance gel permeation chromatography, Fourier transform infrared, nuclear magnetic resonance, scanning electron microscope, thermogravimetric analysis and X-ray diffraction. The molecular weight distributions of GLP were determined as 1.89 × 106 and 1.26 × 104 Da. The monosaccharide composition of GLP was glucose, glucuronic acid, galactose and arabinose with molar ratios of 0.91:0.04:0.03:0.02, respectively. The average molecular weight of GLP80-1 was determined as 1.63 × 104 Da. The structure of GLP80-1 was deduced to be a homogenous glucan, comprised a main chain of (1→4)-linked-α-D-Glcp with a single α-D-Glcp branch substituted at C-6. The results of biological activities in vitro showed that GLP and GLP80-1 exhibited free radical scavenging effects, and displayed promotion for the proliferation of mouse spleen lymphocytes and RAW264.7 cells. The data indicated that GLP and GLP80-1 had the potential to be explored as novel natural antioxidant and immunomodulator for application in functional food.

Inula viscosa (syn Dittrichia viscosa) (sticky fleabane) from the Asteraceae family, is well-known for its pharmacological activities. In this research, anatomical characterization of leaves and st...

In this paper, structure, chemical composition and physicochemical properties of the novel polysaccharide Amuniacum gum (AMG) were assessed. The AMG had 12.21% moisture, 3.76% ash, 0.31% protein, 73.06% carbohydrate, 1.24% fat and 10% uronic acids. The elemental analysis indicated the absence of sulfur. The HPLC demonstrated the presence of galactose and arabinose as dominant sugars. The X-ray diffraction (XRD) pattern of the native gum indicated a semicrystalline structure. Furthermore, gel permeation chromatography (GPC) showed that the average molecular weight included 35 kDa. The Fourier transform infrared (FTIR) spectroscopy showed the presence of hydroxyl, carboxyl and methyl groups. Moreover, 1H and 13C NMR analysis demonstrated that AMG included a backbone of β-D-Galp residues and was mainly branched through 4-O-methyl-α-D-glucopyranosyl units. Results of thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) indicated that the thermal decomposition of AMG occurred at nearly 278 °C. In conclusion, these results highlight that the novel gum can be used in food and pharmaceutical industries.

Amino-derivatized lignocomposite (ADL-composite) has been designed as an artificial lignin polymer (P1) of monolignol (coniferyl alcohol, CA) enhanced by aniline insertion (P2). The derivatized lignopolymeric (P2) layer covered the surface of a methacrylate particles (SC2/SC6) functionalized previously with amino phenolic crosslinker (p-phenylenediamine (p-Ph-2-NH2) or p-amino-2-hydroxybenzoic acid (p-NH2-SalA)). One-pot biocatalytic approach allowed to combine the preparation of the polymeric materials and also its attachment on the particles surface. Thus, the monolignol (CA) will be oxi-copolymerized together with aniline on the amino pre-functionalized support surface. The oxidation process was performed using H2O2 reagent and catalyzed by peroxidase enzyme (horseradish peroxidase, HRP). The biocatalytic process was evaluated in term of aromatic monomers (CA and aniline) conversion. The chemical structure and properties of the resulted ADL-composites were investigated using specific techniques (e.g. FTIR, TPD, TGA, static contact angle, elemental analysis, and gel permeation chromatography). Attachment of P1/P2 polymer on the particles improved the hydrophobicity and also the basicity of the composite surface. Lipase enzyme was immobilized on the ADL-composites for testing the applicability of ADL-composites for biocatalyst preparation. SEM analysis allowed to notice the modification of ADL-composites surface after enzyme immobilization. Immobilized lipase exhibited better activity compared with free lipase demonstrating the efficiency of ADL-composite as support for enzyme immobilization.

Two strategies were investigated to perform the controlled degradation of two grades of poly(butylene succinate) (PBS): the chemical and enzymatic degradation routes. PBS chemical degradation assays were carried out in alkaline and acidic media at the temperature range between 40 and 80 °C. Additionally, the effects of distinct enzymes (cutinase, lipase, cellulase, protease, and amylase) that exhibit distinct hydrolysis activities were investigated on the enzymatic degradation of PBS. Two grades of PBS were compared: PBS microparticles manufactured through suspension polycondensation (PBS1) and; commercial PBS (PBS2) manufactured in bulk processes. Polymer degradation was evaluated through high-performance liquid chromatography, gel permeation chromatography, weight loss analyses, and determination of the pH of the supernatant. It was observed that PBS1 was subject to high rates of chemical degradation at higher temperatures, especially when degradation was conducted in alkaline media. On the other hand, the analyzed operation conditions did not affect the degradability of PBS2 significantly, which fluctuated around 5% of weight loss after 4 weeks. The degradability of both polymer matrices was much more intense when enzymes were used. For PBS1, the enzyme degradation effect was significant (weight loss of 57%, 32%, 25% after 4 weeks of experimentation, using cutinase, lipase, and amylase, respectively); for PBS2, after 1 month of experimentation, the weight loss using cutinase and lipase approached respectively 100% and 81%. It can be concluded that the application of enzymes can be beneficial for the controlled degradation of PBS at mild process conditions, allowing the development of environmental-friendly strategies for the controlled degradation of this material, and that both chemical and enzymatic degradations are sensitive to the characteristics of the analyzed samples, which must be carefully considered during the process development stage.

Within this study, the ZrO2/lignin and ZrO2-SiO2/lignin hybrid materials were obtained for the first time. The mechanical grinding method was used for this purpose. In order to determine the properties of obtained lignin-based hybrids and the components used to produce them, as well as to evaluate the efficiency of their preparation, the authors used such research techniques as scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), elemental analysis, porous structure analysis and thermal stability assessment (TGA/DTG). The next step involved using the components and produced hybrid materials as polymer fillers for poly(methyl methacrylate) (PMMA). The obtained lignin-based hybrid biocomposites have then been thoroughly characterized using gel permeation chromatography (GPC), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA) and hardness testing. All the conducted tests confirm the possibility of using the obtained bio-based products in practice, within the widely understood construction industry, for producing durable building facades or noise barriers, among others.

Hydrotreatment of birch wood pyrolysis liquid (PL) was carried out at 350 °C and 6.0 MPa initial hydrogen pressure (RT) for 4 h in a batch autoclave using promising high-loading Ni-based catalysts stabilized by SiO2. Different additives (Cu, Mo, Cr, P) were used to modify the catalysts. The products in liquid organic (OPh) and aqueous phases (AqPh) after PL hydrotreatment were characterized by different methods, such as gas chromatography-mass spectrometry (GC–MS), Fourier-transform infrared (FTIR) spectroscopy, gel permeation chromatography (GPC), etc. Herein, the performance of the catalysts was evaluated by considering the yield and chemical composition of the products (gaseous phase, OPhs, AqPhs, and coke). For the MoCr-containing system, a higher yield of the aqueous phase with low O/C ratio was observed that could be explained by more effective hydrodeoxygenation of water-soluble compounds due to Ni-Mo-Cr solid solutions and coordinatively unsaturated Cry+ and Mox+ sites. P-modified NiCuMoP-SiO2 and NiCrP-SiO2 catalysts reveal more intense CO2 formation very likely due to decarboxylation over Ni3P particles, thus leading to the decrease in the oxygen content in organic phase to 14 wt.%. Fresh reduced catalysts were examined by CO chemisorption, X-ray diffraction (XRD), and high-resolution transmission electron microscopy (HRTEM) to provide insights into the structure and morphology. High resistance to coke formation was evidenced according to CHNS analysis of spent samples, besides, the stability of catalysts was additionally assessed by X-ray diffraction.

International audience

Acrylonitrile-butadiene-styrene (ABS) is one of the most extensively used engineering polymers and analysing the chemical structure changes during processing and recycling is extremely important. Hence, in this study, an ABS resin was processed using a torque rheometer at different temperatures and for different numbers of cycles. Pyrolysis gas chromatography mass spectrometry (Py-GC/MS) was used to study the effects of the processing parameters on additives. Fourier transform infrared spectroscopy (FTIR), hydrogen nuclear magnetic resonance (1H NMR) spectroscopy, and gel permeation chromatography (GPC) were used to analyse the structural changes in the resin. GPC results showed that after processing at 290 °C using the torque rheometer, large size soluble polymeric components increased. The increase in the large size soluble polymeric components after processing at 290 °C was probably related to the crosslinking reactions in the grafted polybutadiene (PB). Furthermore, chemical analysis of the ABS resin samples after multiple extrusion cycles in a twin-screw extruder indicated that reprocessing considerably affected the ABS resin.

In this work, 2-(4-acetyl-2,6-dichloroanilino)-2-oxoethyl-2-methylprop-2-enoate (CFAOMA) monomer was synthesized and characterized. Then, copolymers of this monomer with glycidyl methacrylate (GMA) were synthesized by the free radical polymerization method at 65 °C in the 1,4-dioxane solvent. Structural characterizations of all compounds were carried out using FTIR, 1H- and 13C-NMR techniques. The composition of the copolymers was determined by elemental analysis. The monomer reactivity ratios were by calculated Finemann-Ross(FR) and Kelen-Tudos(KT) method. Average monomer reactivity ratio values determined by both methods were found as 0.26 for CFAOMA and 0.36 for GMA. The glass transition temperature (Tg) value of polymers was determined by differential scanning calorimetry (DSC). According to the thermogravimetric analysis (TGA) data, the thermal stability of the poly(CFAOMA) was higher than copolymers. The molecular weights (Mw and Mn) and polydispersity index of the polymers were determined by gel permeation chromatography (GPC). The thermal decomposition activation energy (Ea) values of polymers were determined using the Ozawa and Kissinger methods. The Ea values of the copolymer were found between 111.03 and 134.71 kJ/ mol by the Ozawa method and 134.51–109.24 kJ/mol by the Kissinger method. Besides, the photo-stability of the copolymers was investigated. Finally, the biological activity of polymers was investigated against different types of bacteria and fungi.

International audience; Recent advances in instrumentation for high-field Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) have enabled access to ∼70 »000 unique molecular formulas in broadband mass spectral characterization of unfractionated/whole asphaltenes. The results accumulated over a decade highlight the need for an asphaltene molecular model that acknowledges the coexistence of (1) monofunctional and polyfunctional species; (2) island and archipelago structural motifs; and (3) heteroatom-depleted/highly aromatic compounds, as well as atypical species with low aromaticity but increased heteroatom content. Collectively, results from FT-ICR MS, preparatory-scale separations (extrography/interfacial material), gel permeation chromatography, precipitation behavior in heptane:toluene, thermal decomposition, and aggregate microstructure by atomic force microscopy (among other techniques), suggest that the strong aggregation of asphaltenes results from the synergy between several intermolecular forces: π-stacking, hydrogen bonding, London forces, and acid/base interactions. This review presents general features of asphaltene molecular composition reported over the past five decades. We focus on mass spectrometry characterization and expose the reasons why early results supported the dominance of single-core motifs. Then, the discussion shifts to recent advances in instrumentation for high-field FT-ICR MS, which have enabled the detection of thousands of species in asphaltene samples, whose molecular composition and fragmentation behavior in ultrahigh vacuum agree with the coexistence of single-core and multicore structural motifs. Furthermore, evidence that highlights the limitations of commercially available/custom-built ion sources and selective ionization effects is presented. Consequently, the limitations require separations (e.g., chromatography, extrography) to gain more-comprehensive molecular-level insights into the composition of these complex organic mixtures. The final sections present evidence for the role of aggregation in selective ionization and suggest that advanced characterization by both thermal desorption/decomposition and liquid chromatography with online FT-ICR MS detection can be employed to mitigate the effects of aggregation and provide unique insights in molecular composition/structure.

In order to obtain polyurethane micelles with targeting property and excellent stability, Fe3O4-modified magnetic amphiphilic polyurethane (MAPU) was successfully synthesized by grafting amphiphilic polyurethane to the surface of Fe3O4 nanoparticles. The structure of MAPU was confirmed by Fourier-transform infrared spectroscopy, proton nuclear magnetic resonance spectroscopy (1H NMR), gel permeation chromatography and thermogravimetric analyzer. MAPU could form micelles with the particle size of less than 45 nm, and the micelles showed excellent stability of anti-dilution and storage, determined by dynamic light scattering. MAPU micelles had superparamagnetic property, and magnetically targeted property in HeLa cells measured by vibrating sample magnetometer (VSM) and Prussian blue staining method, respectively. Methyltetrazolium (MTT) assay experiment indicated that MAPU micelles were almost non-cytotoxic. In addition, MAPU micelles could encapsulate hydrophobic model drugs such as Indometacin (IMC) and had a release-sustained effect for IMC.

In this study, dried sheets of nori, shredded and processed thalli of the red alga Pyropia yezoensis, were fermented with either barley, rice or soybean koji. High-performance liquid chromatographic analyses of the lipid extracts of the fermented products indicated that the fermentation of nori with all kinds of tested koji released free fatty acids, including the eicosapentaenoic acid, from ester lipids. We found that approximately half of the eicosapentaenoic acid in nori had been released as the free fatty acid at up to 4 weeks of fermentation at 30 °C and more than 65% at 8 to12 weeks in the fermented products with barley and rice koji. We also demonstrated the degradation of porphyran, a major cell wall polysaccharide of nori, by gel chromatography on Sephacryl S-300 HR of hot water extracts of the fermented products of nori with barley koji. Approximately two-third of porphyran had been degraded to porphyran oligosaccharides up to 6 weeks of fermentation. Fermentation of nori with koji may bring out the potential health-promoting functions of nori.

In this study, soluble double-chain (ladder-like) polysiloxane (DC-PS) was successfully prepared by intramolecular polycondensation (template polymerization) of polysiloxane, in which diethoxysilyl groups were introduced into the side chains, using hydrochloric acid and purified water as the catalysts. Based on the solubility, gel permeation chromatography, IR, 1H NMR, 29Si NMR, and transmission electron microscopy (TEM) results, it was found that DC-PS has a structure in which two polysiloxane chains are connected in parallel by urea bonds, although it is slightly defective, as the cyclic trimer component and the silanol group are present. In addition, thermogravimetric analysis (TGA) confirmed that DC-PS showed high thermal stability. Furthermore, a DC-PS cast film had relatively high water repellency, adhesion to a glass substrate, and surface hardness. A soluble double-chain (ladder-like) polysiloxane (DC-PS) with high thermal stability was successfully prepared by intramolecular polycondensation (template polymerization) of a polysiloxane, in which diethoxysilyl groups were introduced into the side chains, using hydrochloric acid and purified water as the catalysts. The DC-PS cast film had coexistence of relatively high water repellency and adhesion to glass.

A novel cyclodextrin-contained copolymer poly(AAc-co-SA-AC-co-allyl-β-CD) was synthesized based on the method of redox radical polymerization. Fourier transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance (1H NMR) spectra were used to study the structure of the obtained copolymer. The molecular weight of the copolymer was studied by gel permeation chromatography (GPC). The polymeric nanoparticles (NPs) were fabricated by a solvent evaporation method. The morphology and particle size distribution of the cargo-free NPs were investigated with transmission electron microscope (TEM), atomic force microscope (AFM), and laser particle analyzer, respectively. Curcumin (Cur) was selected as a model drug and encapsulated into the above NPs. The distribution of Cur in the drug-loaded NPs was analyzed by the method of differential scanning calorimetry (DSC) and X-ray diffraction (XRD). Moreover, the release profiles of Cur from Cur-loaded NPs were studied in pH 6.8 and 7.4 buffers. The results of FTIR and 1H NMR spectra confirmed the successful synthesis of poly(AAc-co-SA-AC-co-allyl-β-CD). GPC curve proved that the molecular weight of the copolymer was more than 60 kDa. TEM and AFM images illustrated that the cargo-free NPs were in spherical shape with a diameter about 40 nm. XRD patterns and DSC curves indicated that most of Cur distributed in the Cur-loaded NPs with amorphous state. Importantly, the medicated NPs showed sustained release characteristics toward Cur.

Aims: To encapsulate a purified bacteriocin into a nanovesicles and check its antibacterial effect. Background: Although the use of nano-encapsulated bacteriocins in food matrices is poorly reported, encapsulated nisin can reduce L. monocytogenes counts in whole and skimmed milk and in soft cheese. Objective: The present study deals with the extraction and purification of a bacteriocin from an isolated strain Pediococcus pentosaceus KC692718. A comparative study of the effect of free pediocin and liposome encapsulated pediocin against Listeria sp. was performed. Methods: The purification of the extracted cell free supernatant was subjected to ammonium sulphate precipitation, cation exchange chromatography followed by gel permeation chromatography. The bacteriocin activity and protein concentration were determined using Lowry’s method. The characterization of the pure pediocin was done. Liposome like nanovesicle was constructed and the stability of the liposome encapsulated pediocin was checked. Finally, the antibacterial effect was comparatively studied of the free pediocin, liposome, and liposome encapsulated pediocin simultaneously. Results: The pediocin of 3.6kDa was purified with a specific activity of 898.8. AU/mg. It remained stable from pH 2.0-8.0 was found to be moderately stable above 80°C and remain stable for one month when stored at -20°C. The encapsulated pediocin showed stability since it retained 50% of its initial activity. The encapsulated pediocin showed 89% of encapsulation efficiency. Conclusion: The encapsulated pediocin not only improved pediocin stability but also enhanced the controlled release of the antimicrobial substances, enough for inhibiting the foodborne pathogen L. monocytogenes.

Biodegradable plastics, such as poly(lactic acid) (PLA), are considered the alternative for alleviating the environmental issues caused by the accumulation of petroleum-based plastic wastes. However, PLA is relatively expensive, and its natural degradation is slow. Therefore, upcycling instead of disposing of PLA should be more favorable for sustainability. Herein, we studied the selective methanolysis of PLA to produce methyl lactate (ML) catalyzed by a new molecular catalyst, tetramethylammonium fluoride (TMAF), with superior thermal and chemical stability and excellent catalytic performance. The complete methanolytic depolymerization of the commercial PLA pellets, 4043D, 6060D, 6202D, and 2500HP, was achieved within a short reaction time ( gel permeation chromatography (GPC) and Nuclear Magnetic Resonance (NMR) spectrometry were used to investigate the mechanism of the PLA depolymerization in the methanol solvent. F - was found to be the active center of the TMAF catalyst. A possible random scission depolymerization pathway of the TMAF catalyzed methanolysis of PLA was proposed.

A near-infrared (NIR) mechanophore was developed and incorporated into a poly(methyl acrylate) chain to showcase the first force-induced NIR chromism in polymeric materials. This mechanophore, based on benzo[1,3]oxazine (OX) fused with a heptamethine cyanine moiety, exhibited NIR mechanochromism in solution, thin-film, and bulk states. The mechanochemical activity was validated using UV-vis-NIR absorption/fluorescence spectroscopies, gel permeation chromatography (GPC), NMR, and DFT simulations. Our work demonstrates that NIR mechanochromic polymers have considerable potential in mechanical force sensing, damage detection, bioimaging, and biomechanics.

In this study, molecular composition of hamster and rat blood was studied by gel permeation chromatography under natural (NH) and artificial hibernation (AH). The control group was represented by 5 fractions of molecules in hamsters and 7 in rats. The areas under peaks of the fractions similar in molecular weight in hamsters and rats were larger in rats. NH was characterized by appearance of new fractions (1,350, 2,350, and 6,350 Da) and an increase in areas under peaks of the control fractions (1,140 and 1,980 Da). Artificial hibernation in rats led to an increase in areas under peaks of 1,140 Da fraction, a decrease in that of 530 Da, and disappearance of 1290 Da, as well as the appearance of new fractions (650, 830, 950, 2350, and 5110 Da). Two hrs of later AH, the areas under peaks of 1,140 and 1,520 Da fractions were greater and that of 530 Da was lesser; 650, 2,350 and 5,110 Da fractions disappeared, 1,290 Da reappeared and new fraction of 4,030 Da appeared. New fractions of 5,820 and 6,530 Da were found 24 hrs later. In hamsters under AH, the areas under peaks of 1,140, 1,600, and 3,330 Da increased; as well as a new peak in 5,280 Da appeared, both in the control rats and those in 24 hrs after AH. Probl Cryobiol Cryomed 2021; 31(3): 191–202

To study the influence of the micromorphology and structure of modified asphalt on pavement performance under combined action of multiple modifiers, styrene–butadiene–styrene, styrene–butadiene–rubber, stabilizer and furfural extract oil were selected to modify the matrix asphalt, and short-term aging experiments were carried out. The cross-linking and distribution of the modifiers were analyzed by fluorescence microscopy, the micromorphology of the modified asphalt before and after short-term aging was analyzed by scanning electron microscopy, and the change in molecular weight of the modifier and asphalt phase was analyzed by gel permeation chromatography. The results showed that the content of saturated and aromatic of Panjin asphalt was more than 65%, and the content of aromatic was more than 33%, which was suitable for simultaneous modification of multiple modifiers with good modification effect. After the stabilizer and the compatibilizer were added, the interface adsorption layer between the modifier particle and the asphalt phase was stable under the action of the active free radicals. The surface morphology of the matrix asphalt changed greatly after aging. The modifier did not further aggravate the folds on the surface of the asphalt after aging, but the aging process was accompanied by the decomposition of modifier macromolecules and the aggregation of small molecules. In the aging process of the composite modifiers, the degradation of macromolecules was the main molecular reaction, while the polymerization reaction was the main reaction of asphalt phase. The conclusions could provide theoretical and technical support for the development and application of high-performance modified asphalt.

The electron beam irradiation (EBI) of native lignin has received little attention. Thus, its potential use in lignin-based biorefineries is not fully understood. EBI was applied to selected lignin samples and the structural and chemical changes were analyzed, revealing the suitability, limitations, and potential purpose of EBI in wood biorefineries. Isolated milled wood, kraft, and sulfite lignin from beech and eucalyptus were subjected to up to 200 kGy of irradiation. The analysis included gel permeation chromatography for molar masses, heteronuclear single quantum coherence (HSQC)- and 31P NMR and headspace gas chromatography-mass spectrometry for functional groups, and thermogravimetric analysis for thermal stability. Most samples resisted irradiation. Subtle changes occurred in the molecular weight distribution and thermal stability of milled wood lignin. EBI was found to be a suitable pretreatment method for woody biomass if the avoidance of lignin condensation and chemical modification is a high priority.

Functional polycarbonate polyols have been synthesized by CO2/propylene oxide (PO) copolymerizations using various Zn(II)-Co(III) double metal cyanide (DMC) catalysts bearing α-, β-, γ-, and δ-dicarbonyl complexing agents (CAs) including dicarboxylic acids, diesters, ketoester, and diketones. The resultant heterogeneous catalysts are intensively characterized by infrared, absorption and X-ray photoelectron spectroscopies, X-ray powder diffraction, and elemental analysis. The produced polycarbonate polyols are characterized using infrared and nuclear magnetic resonance spectroscopies, gel permeation chromatography, differential scanning calorimetry and thermogravimetric analysis measurements. The catalysts bearing β-, γ-, and δ-dicarbonyl CAs exhibit high activity towards CO2/PO copolymerization and produce polycarbonate polyols with high carbonate content, wide range of molecular weight and narrow polydispersity. The functionality of the resultant polycarbonate polyols varies depending on the type of CAs and the functionality of initiators.

The structures and immunomodulatory activities of two polysaccharides (SDH-WA and SDH-0.2A) from Rehmanniae Radix Praeparata (RRP) were investigated. RRP crude polysaccharide was obtained by water extraction and purified. Ion chromatography, high-performance gel permeation chromatography, Fourier-transform infrared spectroscopy, methylation analysis, gas chromatography-mass spectrometry, and nuclear magnetic resonance were used to characterize the polysaccharides. The main chain of SDH-WA was →6)-α-D-Galp-(1→6)-α-D-Galp-(1→5)-α-L-Araf-(1→3,5)-α-L-Araf-(1→, terminal sugar residue α-L-Araf-(1→ linked to residue →3,5)-α-L-Araf-(1→ on the main chain by an O-3 bond. The other two terminal sugar residues α-D-Galp-(1→ and →6)-β-D-Galp were linked to the end of the main chain. The main chain of SDH-0.2A was →2,4)-α-L-Rhap-(1→4)-α-D-GalpA-(1→. Three branched chains α-D-Galp-(1→6)-α-D-Galp-(1→5)-α-L-Araf-(1→3,5)-α-L-Araf-(1→, →3,6)-β-D-Galp-(1→5)-α-L-Araf-(1→, and →4)-β-D-Galp-(1→5)-α-L-Araf-(1→ were linked to the main chain residue →2,4)-α-L-Rhap-(1→ by an O-2 bond. Three terminal sugar residues α-D-Galp-(1→, α-L-Araf-(1→, and →6)-β-D-Galp were linked to the end of the chain. Both polysaccharides showed no cytotoxic effects on and significantly promoted the phagocytic activity of RAW264.7 cells. They dose-dependently improved lysozyme activity and stimulated the production of TNF-α and IL-6 by RAW264.7 cells, but attenuated the secretion of lysozymes, TNF-α, IL-6, IL-1β, and nitric oxide by lipopolysaccharide-induced RAW264.7 cells. The present studies suggest that PRR polysaccharide is a valuable source with immunomodulating.

New four-arm star poly(ether urethanes) (star PUs) based on erythromycin propionate core are presented. Toluene 2,4-diisocyanate (TDI) and 4,4′-methylenebis (phenyl isocyanate) (MDI) as diisocyanates and Terathane of different molecular weights as polyether arms were employed in their synthesis in order to study their structure-property relationship. The synthesized star PUs were analyzed through IR and 1H NMR spectroscopies, gel permeation chromatography, X-ray diffraction, thermogravimetry, differential scanning calorimetry. The IR spectral changes obtained on heating the samples were investigated. Disc-diffusion method was employed for antimicrobial tests. The values of the glass transition temperature are higher than those of starting polyethers attributable to the influence of the more rigid erythromycin propionate core bearing urethane groups. The melting temperatures corresponding to soft polyether arms are in the melting temperature range of starting polyethers. At higher temperatures melting phenomena associated to hard urethane core are obtained. The IR spectra recorded at various temperatures reveal that the composition of the hard segment having MDI in the structure ensures higher conformation stability during heating process. The crystalline peaks in the X-ray diffractograms are consequence of polyether arms crystallinity. MDI and higher polyether molecular weight increase the thermal stability. The values of hydrodynamic radii increase with increasing polyether arm length and are higher for TDI star PUs than MDI star PU because of the expanded structures of the former ones. The antibacterial study reveals that for hospital S. aureus strain the diameters of inhibition zones are lower than for S. aureus ATCC 25923.

Silk sericin (SS) is a natural polymer widely studied in the design of biodegradable materials for cosmetic, biomedical, food, and chemical applications. This work was designed to explore the molecular and structural characteristics of SS extracted from different silk sources with different processing degrees: high-quality cocoons (NCs), defective cocoons (DCs), and raw silk yarn (Y). The last two sources have been less studied. SS solutions were obtained from each source using the high-temperature and high-pressure degumming method (HTHP). The molecular weight distribution and amino acid composition of SS extracts were determined using gel permeation chromatography (GPC) and reversed-phase chromatography (RP HPLC), respectively. SS films were formed from each solution and then characterized by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), nuclear magnetic resonance spectroscopy (NMR), and differential scanning calorimetry (DSC). Water uptake and degradation of SS films were also evaluated. The molecular characteristics of SS extracts were related to the processing degree of the silk source. Moreover, the properties of SS films seemed to be dominated by the primary structure and the presence of natural impurities in each extract. The results suggest that silk sources could be selected ad hoc to design SS materials with distinctive properties for specific applications. Three different silk sources were explore for sericin (SS) extraction and film formation. Features of each raw material, especially the degree of processing, have remarkable effects on the primary structure and the presence of nonprotein compounds in the sericin extract. As a result, sericin films exhibited distinctive properties that seemed to be correlated with the amount of natural impurities and the molecular properties of the SS extract obtained from each raw material.

The preparation of mock-ups in heritage science studies represents a valid alternative for investigation purposes, avoiding extensive sampling of cultural heritage objects. This work presents for the first time the successful preparation of three dimensional (3D) mock-ups made of celluloid, considering a combination of historical industrial production strategies and small-scale lab facilities. Prefabricated transparent celluloid sheets were acquired and then shaped through compression molding for creating mock-ups with 3D geometries. These reflected common and representative shapes encountered in the collection of the Deutsches Museum. Visual inspection of the mock-ups allowed determining the best compression molding conditions. Attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR) confirmed the absence of molecular heterogeneity due to the processing method. Artificial aging of the mock-ups was conducted to reach degradation states comparable with naturally aged objects. ATR-FTIR investigation offered first insights into the induced artificial degradation. Ion chromatography (IC) and gel permeation chromatography (GPC) analyses allowed to assess the extent of the artificial aging of the celluloid mock-ups and confirmed the occurrence of loss of camphor, denitration, and main chain polymer scission, the latter being the predominant decay path. The comparison with historical objects highlighted that the mock-ups are representative of moderately aged artifacts. As such, this study paves the way for implementing moderately aged celluloid 3D mock-ups in heritage science research, enabling in-depth testing for the scope of conservation.

Salt is very important for human health and food seasoning. Recently, several peptides isolated from natural food products have been reported exhibiting a salty taste or a saltiness-enhancing function. In this investigation, taste-active peptides occurring in commercial Chinese fermented soybean curd were isolated and identified using ultrafiltration, gel permeation chromatography, ion-exchange chromatography, and nano-LC/Q-TOF MS/MS. The salty taste-enhancing function of the target fractions was confirmed by both a rat taste cell model and/or human sensory evaluation. Four decapeptides were found as taste-active compounds. Among them, peptide E (EDEGEQPRPF) was the most potent saltiness-enhancing peptide: 0.4 mg/mL in 50 mmol/L NaCl solution could increase its salty perception equivalent to the salt level of 63 mmol/L NaCl reference solution. The sequence of the peptide has been found in the α'-subunit of β-conglycinin [Glycine max]. The remaining peptides V (VGPDDDEKSW), DD (DEDEQPRPIP), and DG (DEGEQPRPFP) showed umami and kokumi tastes as well as a weak saltiness-enhancing sensation. These findings suggest that the decapeptide EDEGEQPRPF could be a possible alternative to partially reduce the amount of sodium intake without compromising for saltiness.

A series of biodegradable poly(e-caprolactone)–poly(ethylene glycol)–poly(e-caprolactone) (PCL–PEG–PCL) (PCEC) triblock copolymers had been successfully synthesized by ring-opening polymerization of e-caprolactone initiated by PEG, which were characterized by proton nuclear magnetic resonance analysis (1H NMR), gel permeation chromatography (GPC), differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR). The gel–sol phase transition diagram of synthesized copolymers was recorded using test tube inverting method. PCECs could form injectable solutions via self-assembly and automatically turned into non-flowing gels at physiological temperatures. Their aqueous solution displayed special gel–sol transition behavior with temperature increasing from 0 to 60°C, when the polymer concentration was above corresponding critical gel concentration (CGC). In vitro release experiments at pH 7.4 showed that after 24 h at least approximately 75–80% of doxorubicin (DOX) can be protected from enzyme or hydrolytic degradation. Therefore, thermosensitive PCECs have many advantages, such as simple drug formulation, no organic solvent, a sustained drug release behavior.

A rapid and easy to use method for monitoring transformations of heavy oil fractions during secondary processes of oil refining is proposed. The method is based on the study of changes in the molecular weight characteristics by gel-permeation chromatography (GPC) using a refractometric detector. Optimal conditions for registration of the chromatograms (temperature, eluent consumption and its composition) were specified. Heptane, toluene, and toluene added with 1% and 5% of methanol were studied as eluents, the polarity indices being arranged in a series 0.2; 2.4; 2.43; 2.54. The effect of the nature of the solvent on the type of the product chromatogram is determined. It is shown that addition of a polar solvent to a nonpolar one increases the polarity index, reduces both the degree of association of petroleum molecules and adsorption on the gel. The most available toluene which meets the GPC requirements is chosen as an eluent. Addition of 1% CH3OH to the eluent promotes suppression of polyelectrolyte effects and adsorption. The revealed absence of the dependence of the retained volume and the type of chromatograms on the eluent flow rate and temperature indicates that separation is carried out under conditions of exclusion and completely obeys the theory of exclusive liquid chromatography. The transformation of raw materials during a technological process of oil production at the JSC «ANKhK» was studied using the GPC method under above-mentioned chromatographic conditions. We have studied vacuum distillate of the primary oil refining unit ELOU+AVT-6 (VD) and the product of hydrocracking of the vacuum distillate of the 123PM unit (HVD). It is shown that determination of the molecular weight characteristics provides an important information about the behavior of technological processes. The HVD meets the requirements for hydrocracking products. A decrease in the content of aromatic hydrocarbons in comparison with the raw feedstock is proved by the data of thin layer chromatography (TLC).

In the present work, polyaluminophenylsiloxanes have been obtained by two methods: the first one consisted in the exchange of sodium phenylsilanolate with aluminum chloride in an anhydrous medium (dimethyl sulfoxide-toluene), while the second one—in the reaction of aluminum acetylacetonate with polyphenylsiloxane under the conditions of mechanochemical activation. The polymers were purified by re-precipitation in the first case and by toluene extraction in the second case. The obtained aluminophenylsiloxanes have been studied by the methods of gel chromatography, diffractometry, and IR and 13C, 29Si, and 27Al NMR spectroscopy. It has been shown that the interaction under the conditions of mechanochemical activation proceeded in two directions: the Si–O–Si bond splitting reaction and the condensation reaction. A comparison of the physical and chemical characteristics of polyaluminophenylsiloxanes has been carried out, and it has been demonstrated that the structure of the PAlPhSi is structurally more homogeneous; aluminophenylsiloxy fragments were present along with siloxyaluminoacetylacetone fragments in PAl(acac)PhSi, which significantly complicated the polymer structure.

In this paper, a cyclotetrasiloxane modified with epoxy resin was synthesized via hydrosilylation with 1, 3, 5, 7-tetramethylcyclotetrasiloxane (D4H) and 4-vinyl-1-cyclohexane 1, 2-epoxide (VCHO). The structure of tetramethylcyclotetrasiloxane modified with cyclohexane epoxide (D4H–VCHO) was characterized by Fourier transform infrared (FT-IR), 1H nuclear magnetic resonance (1H-NMR) and gel permeation chromatography (GPC). The effects of feeding methods, feeding ratios, catalyst dosages, reaction temperature and reaction time on the products were investigated. After 4-h reaction with 8 ppm catalyst at 90 °C, D4H–VCHO was obtained with an epoxy value of 0.521 and a refractive index of 1.4920. Then, with 4-methylhexahydrophthalic anhydride as a curing agent and tetrabutylammonium bromide as a catalyst, the obtained D4H–VCHO was cured at 90 °C for 1 h and then 120 °C for another hour. The cured products showed high light transmittance, strong thermal stability, suitable hardness and low water absorption. The glass transition temperature of cured materials was 151.6 °C, indicating the improvement of flexibility. In addition, the introduction of epoxy groups greatly enhanced the adhesion of silicone resins to substrates. The results demonstrated that the epoxy-modified silicone materials could be applied as LED packaging materials.

In this study, a biomass pretreatment strategy with a recyclable cosolvent (toluene sulfonic acid/ethanol) was developed. The low boiling point solvent (78.15 °C), ethanol, was employed to replace water in the cosolvent system for reducing energy consumption of solvent evaporation. Under a mild temperature (80 °C), the lignin removal and enzymatic saccharification yield of glucan reached to 49.27% and 93.28%, respectively. The obtained lignin was characterized with fourier transform infrared spectroscopy, 31P nuclear magnetic resonance spectroscopy, gel permeation chromatography, and two-dimensional H–C heteronuclear single quantum coherence nuclear magnetic resonance spectroscopy. Meanwhile, the interaction mechanism of lignin and cosolvent molecules was explored by density functional theory calculation and molecular dynamics simulations. The results showed that water molecules significantly enhanced the noncovalent interactions, mainly the C–H⋯π and H–O···H bonding, as revealed by an increase of interaction energy ΔE. By disrupting the natural hydrogen bonds, the fractionated lignin was thereby dissolved out from wood material.

A novel β-glucosidase was purified from pumpkin (Cucurbita moschata) seed by anion exchange chromatography and gel permeation chromatography, and its molecular mass was determined to be 42.8 kDa by gel permeation chromatography. The heterodimeric structure consisting of two subunits, free from disulfide bonds, was determined by native-PAGE analysis followed by zymography. The enzyme was maximally active at pH 4.0 and 70°C, and Vmax, Km, and kcat values were 0.078 units mg−1 protein, 2.22 mM, and 13.29 min−1, respectively, employing p-nitrophenyl-β- d -glucopyranoside as the substrate. The high content of glycine determined by amino acid analysis implies that the enzyme possesses flexible conformations and interacts with cell membranes and walls in nature. Circular dichroism studies revealed that the high stability of the enzyme within the pH range of 2.0–10.0 is due to its reversible pH-responsive characteristics for α-helix–antiparallel β-sheet interconversion.

To improve comprehensive properties of poly(butylene adipate-co-terephthalate) (PBAT), especially thermal stability, reactive extrusion method was used to modify PBAT. Branch and micro cross-linking structure of PBTA was produced with hexanediol diglycidyl ether (HDGE), polyethylene glycol diglycidyl ether (PEGDGE), and styrene–methyl methacrylate–glycidyl methacrylate terpolymer (KL-E4370) as the chain extender (CE), demonstrated through differential scanning calorimeter, Vicat softening point testing (VSP), gel permeation chromatography, rheological measurement, and scanning electron microscopy. The molecular weight, the complex viscosity, and the viscoelasticity of modified PBAT were improved by increasing the CE molecular weight. The crystallization temperature and VSP were also increased. Meanwhile, it showed that the hydrolysis resistance of PBAT was improved and its degradation performance was decreased. Furthermore, when KL-E4370 was added, PBAT has the best comprehensive performance.

This study aimed to hydrolyze lentil protein from two hydrolysis stages: single and sequential hydrolysis using Alcalase (1, 2, and 4% w/w enzyme to substrate (E:S)) and Flavourzyme (2% w/w) through a processing time of 180 min with an interval of 30 min, and then, degree of hydrolysis (DH), antioxidant and angiotensin-converting enzyme (ACE)-inhibitory activities, phenolic compounds, amino acid composition, molecular weight (MW) distribution, molecular weight profile, sensory, and functional properties were evaluated. The highest DH (47.05%), ACE-inhibitory (0.25 mg/mL), and phenolic compounds (3.84 mg GAE/g) were obtained when sequential hydrolysis was accomplished at Alcalase and Flavourzyme concentrations of 2% w/w and hydrolysis time of 120 and 60 min, respectively. Hydrolysis did not change the main amino acid profile. Despite this, the amino acids which contribute to umami taste were increased after hydrolysis. According to Sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS-PAGE) results, the lowest MW peptides were produced by sequential hydrolysis which was agreed by gel permeation chromatography (GPC) (4.4 kDa and 100 Da). Sensorial analysis indicated that peptides produced by Alcalase at 1% w/w concentration with hydrolysis time of 180 min (Al-1%-180 min, DH value of 15.72%) had the highest bitter taste and further hydrolysis led to reduction of bitter taste and sweetness was increased for Flavourzyme (Fl-2%-180 min) and also sequential hydrolysis produced peptides. Alcalase digests indicated higher solubility than control and Flavourzyme digest. The emulsifying activity index (EAI) was decreased (35.2 to 21.5%) while Foaming capacity (FC) was increased (80 to 104.76%) by Alcalase hydrolysis.

Natural rubber latex (NRL) is a green and highly potential material for various rubber product applications such as tyres, belts, gloves, and foams. To enhance its application, NRL requires rubber chemicals and other additives to improve its processibility and properties. Epoxidised natural rubber (ENR) is a unique polymer generated through the epoxidation process that replaces the double bonds in the NR polymer chain with an epoxy group. There is a potential to use ENR in its latex form (ENRL) to produce dipped products. One of the vital factor to indicate ENRL suitability for producing dipped products is its biodegradability. This work investigates the biodegradability of ENRL films in a controlled composting environment under laboratory conditions. The degree of biodegradation is measured based on evolved carbon dioxide produced by microorganism activities in aerobic condition. The influence of microbial population on the biodegradation and mineralization rate of ENRL films in the composting environment is discussed. The morphological and chemical changes of the ENRL films were observed and analyzed using scanning electron microscopes, Fourier-transform infrared spectroscopy, gel permeation chromatography and weight loss. Results obtained from this study can be used to predict the preliminary biodegradation rate of ENRL films.

The paper presents the results of research on the influence of used plasticizing system on the structural and thermal properties of thermoplastic starch (TPS). The thermoplastic starch granulate was obtained by extrusion of native starch in the presence of a plasticizing system using a twin-screw extruder. Glycerol and urea were used as plasticizers in various proportions. In order to evaluate the effectiveness of the starch plasticization process, changes in its chemical structure were analyzed by infrared spectroscopy (FTIR), gel permeation chromatography (GPC) and X-ray diffraction (XRD). TPS thermal stability was determined by thermogravimetric analysis (TGA). An improvement in the efficiency of the plasticization process has been found for a urea-containing plasticizing system compared to the composition of starch plasticized only with glycerol. In addition, the XRD analysis confirms the beneficial effect of urea on the inhibition of starch retrogradation process.

Mutan is an extracellular sticky polymer having α-1-3 and α-1-6 glycosidic linkages with a large diversity in molecular weights and structures depending on the source. These compounds are reported to be highly thermostable and also have potential physiochemical and biological applications. The main aim of this review is to provide an overview of glucosyltransferases and their role in mutan synthesis. The production strategies and structural properties of bacterial mutans are discussed with a goal to improve production efficiency. The physicochemical features, chemical modifications, potential industrial applications and future prospects are also discussed. According to data, mutan and its derivatives will play a larger role in medicinal sectors and as thermoplastics in the near future.Abbreviations: ABTS: 2,2'-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid; BHI: Brain heart infusion broth; 13C (HSQC) NMR: Heteronuclear Single Quantum Coherence NMR; CBMs: Carbohydrate binding modules; DPPH: 2,2-diphenyl-1-picrylhydrazyl; FTIR: Fourier-transform infrared spectroscopy; GC-MS: Gas chromatography-mass spectrometry; GPC: Gel permeation chromatography; Gtfs: Glucosyltransferases; 1H (DQF-COSY): Double-quantum filtered correlation spectroscopy; HPAEC-PAD: High-performance anion exchange chromatography with pulsed amperometric detection; HPLC: High performance liquid chromatography; HPSEC-RI: High-performance size exclusive chromatography coupled with refractive index; HPSEC-MALLS: High-performance size exclusive chromatography with multi-angle laser light scattering detection; MALDI-TOF: Matrix-Assisted Laser Desorption/Ionization-Time of Flight mass spectrometry; Mw: Weight-average molecular weight; MWD: Molecular weight distribution; NMR: Nuclear magnetic resonance spectroscopy; TEM: Transmission electron microscopy; THB: Todd Hewitt Broth; TTY: Tryticase tryptose yeast extract broth.

The aim of this study was to fabricate novel microparticles (MPs) for efficient and long-term delivery of amikacin (AMI). The emulsification method proposed for encapsulating AMI employed low-molecular-weight poly(lactic acid) (PLA) and poly(lactic acid-co-polyethylene glycol) (PLA-PEG), both supplemented with poly(vinyl alcohol) (PVA). The diameters of the particles obtained were determined as less than 30 μm. Based on an in-vitro release study, it was proven that the MPs (both PLA/PVA- and PLA-PEG/PVA-based) demonstrated long-term AMI release (2 months), the kinetics of which adhered to the Korsmeyer-Peppas model. The loading efficiencies of AMI in the study were determined at the followings levels: 36.5 ± 1.5 μg/mg for the PLA-based MPs and 106 ± 32 μg/mg for the PLA-PEG-based MPs. These values were relatively high and draw parallels with studies published on the encapsulation of aminoglycosides. The MPs provided antimicrobial action against the Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumoniae bacterial strains. The materials were also comprehensively characterized by the following methods: differential scanning calorimetry; gel permeation chromatography; scanning electron microscopy; Fourier transform infrared spectroscopy-attenuated total reflectance; energy-dispersive X-ray fluorescence; and Brunauer-Emmett-Teller surface area analysis. The findings of this study contribute toward discerning new means for conducting targeted therapy with polar, broad spectrum antibiotics. © 2021 The Authors. Published by American Chemical Society., Polish program for PhD students entitled "InterPhD2: The development of interdisciplinary and international PhD study programs" [POWR.03.02.00-00I002/16]; Ministry of Education, Youth and Sports of the Czech Republic, DKRVO grant [RP/CPS/2020/002], Ministerstvo Školství, Mládeže a Tělovýchovy, MŠMT: RP/CPS/2020/002

Novel macro-xanthate agents containing azo initiator and polyethylene glycol (PEG) were synthesized to prepare block copolymers via macromolecular design by an interchange of xanthate (MADIX) polymerization. In this system, the multifunctional agents were used as both macromolecular chain transfer agents and free radical sources. Polystyrene–polyethylene glycol–polystyrene (PS-PEG-PS) copolymers were prepared easily with molecular weight (Mn) from 23,000 to 43,000 g/mol by MADIX copolymerization of styrene using PEG-N = N-PEG (Mn, PEG = 600, 1000, 1500, and 3000 g/mol) as the macro-MADIX agents. In this process, the molar mass (Mn) increased over time for a controlled MADIX polymerization process, but the polydispersity varied slightly. The controlled polymerizations showed typical living properties, and polymers having low polydispersity (below Đ

The main chain of polyolefin was synthesized by copolymerization of 4 — vinylbenzyl chloride (VBC) and acrylonitrile (AN), and trimethylamine is used for quaternization to prepare heterogeneous benzyl trimethyl-ammonium anion exchange membranes (Heter-X) and homogeneous benzyl trimethyl-ammonium anion exchange membrane (Homo-X). The results of Fourier-transform infrared (FT-IR), gel permeation chromatography (GPC), and 1H nuclear magnetic resonance (NMR) showed that VBC and AN were successfully copolymerized to form a polymer with a certain molecular weight, and trimethylamine was successfully quaternized. The prepared membranes exhibited good thermal stability and mechanical properties. The theoretical ion exchange capacity (IEC) values of Homo-3 and Heter-3 are the same, but the conductivity at 80 °C were 0.0572 S cm−1 and 0.0505 S cm−1. The results showed that the homogeneous method has a higher degree of quaternization and a more uniform distribution of quaternary ammonium groups, forming a more obvious microphase separation structure, which can also be seen in the atomic force microscopy (AFM) diagram. After being soaked in 1 M KOH solution for 480 h, the ionic conductivity of Homo-6 and Heter-6 can still remain 91.4% and 85.5%, and the IEC loss rates were 17.21% and 24.34%. These results indicate that the prepared membranes are promising materials for application in fuel cells.

Polyvinyl benzyl chloride (PVBC) was synthesized by free radical polymerization of 4-vinylbenzyl chloride using benzoyl peroxide initiator at 60 °C. PVBC was synthesised in different solvents such as toluene, xylene, 1,4-dioxane, and tetrahydrofuran. The polymers were structurally characterized by 1H NMR and FTIR spectroscopic techniques. The thermal property of the polymer was investigated by thermogravimetric analysis (TGA) and differential thermogravimetric analysis (DTA).The number average molecular weight, weight average molecular weight and polydispersity index of PVBC synthesised in different solvents were determined and compared by gel permeation chromatography technique.