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wszystkich: 84
Wyniki wyszukiwania dla: CARBOHYDRATE
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Thermosensitive composite based on agarose and chitosan saturated with carbon dioxide. Preliminary study of requirements for production of new CSAG bioink.
PublikacjaThis study introduces a method for producing printable, thermosensitive bioink formulated from agarose (AG) and carbon dioxide-saturated chitosan (CS) hydrogels. The research identified medium molecular weight chitosan as optimal for bioink production, with a preferred chitosan hydrogel content of 40–60 %. Rheological analysis reveals the bioink's pseudoplastic behavior and a sol-gel phase transition between 27.0 and 31.5 °C. The...
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Synthesis, the crystal structure, and high-resolution NMR spectroscopy of methyl 4-O-acetyl-3-azido-2,3,6-trideoxy-6-iodo-ŕ-D-arabino-hexopyranoside
PublikacjaW wyniku wieloetapowej syntezy otrzymano glikozyd metylowy 4-O-acetylo-3-azydo-2,3,6-trideoksy-6-jodo-ŕ-D-arabino-heksopyranozy. Związek wykazuje konformację 4C1, co wykazano na podstawie wysokorozdzielczej spektroskopii1H i 13C NMR oraz rentgenowskiej analizy strukturalnej monokryształu. W pracy scharakteryzowano również 7 nowych związków otrzymanych jako produkty pośrednie i uboczne.
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The solvent-free thermal dehydration of hexitols on zeolites
PublikacjaPodczas termicznej dehydratacji heksytoli w obecności zeolitów otrzymano szereg produktów zachodzących zarówno z inwersją lub retencją konfiguracji przy asymetrycznych atomach węgla. Produkty rozdzielano i identyfikowano przy pomocy chromatografii i spektroskopii NMR. 1,4:3,6-dianhydroiditol scharakteryzowano przy pomocy rentgenowskiej analizy strukturalnej.
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X-ray diffraction and high-resolution NMR spectroscopy of methyl 3azido-2,3-dideoxy-ŕD-lyxo-hexopyranoside
PublikacjaOpisano strukturę 3-azydo-2,3 dideoksy-ŕ-d-lykso-heksopiranozydu metylu na podstawie danych otrzymanych przy pomocy rentgenowskiej analizy strukturalnej oraz wysokorozdzielczej spektroskopii magnetycznego rezonansu jądrowego. Przedyskutowano również wpływ pierścieniowego atomu tlenu na wartości stałych sprężeń atomów wodoru przy atomach C6 i C1 pierścienia 2-deoksy-D-lyksooraz-D-ksylo-heksopiranozydów.
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Microwave-assisted silication of potato starch
PublikacjaSilication of potato starch was performed by microwave irradiation and convectional heating of starch with sodium metasilicate. The study has shown that microwaves offered more selective silication thanconvectional heating. Depending on the dose of metasilicate products of either monoesterification or crosslinking esterification were formed. Increase in the amount of the silicating agent favoured crosslinking of starch. In the...
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Structure and properties of the exopolysaccharides produced by Pseudomonas mutabilis T6 and P. mutabilis ATCC 31014
PublikacjaThis paper presents a study on the purification, primary structure, and rheological properties of exopolysaccharides isolated from cultures of Pseudomonas mutabilis T6 and P. mutabilis ATCC 31014. Both polymers are exopolysaccharides of D-mannose. The mannan isolated from P. mutabilis T6 contains on average about 5% of residual b-D-glucose, in contrast to the mannan from P. mutabilis ATCC 31014, which contained only trace amounts...
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Synthesis and antimicrobial activity of 6-sulfo-6-deoxy-D-glucosamine and its derivatives
Publikacja6-Sulfo-6-deoxy-D-glucosamine (GlcN6S), 6-sulfo-6-deoxy-D-glucosaminitol (ADGS) and their N-acetyl and methyl ester derivatives have been synthesized and tested as inhibitors of enzymes catalyzing reactions of the UDP-GlcNAc pathway in bacteria and yeasts. GlcN6S and ADGS at micromolar concentrations inhibited glucosamine-6-phosphate (GlcN6P) synthase of microbial origin. The former was also inhibitory towards fungal GlcN6P N-acetyl...
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Collagen and hyaluronic acid hydrogel in water-in-oil microemulsion delivery systems
PublikacjaThe efficacy of microemul-sion in dermal and transdermal delivery of active ingredients. Here, we assessed the water-in-oilmicroemulsion capacity to incorporate two natural polymers, i.e. collagen and hyaluronic acid withlow and high molecular weight. Systems were extensively characterized in terms of conductivity, phaseinversion studies, droplet diameter, polydispersity index and rheological properties. The results of thisresearch...
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Investigation of an elutable N-propylphosphonic acid chitosan derivative composition with a chitosan matrix prepared from carbonic acid solution
PublikacjaPorous chitosan composites using CO2 dissolution procedure and including water soluble N-propylphosphonic chitosan derivative (p-CHI) were obtained and characterized. In contrast to the control material, composites containing modified chitosan distinguished by a rapid moisture absorption and good adhesion to the skin. The FTIR analysis confirmed the presence of propylphosphonic group in the structure of the polymer. The porosity...
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Microwave-assisted preparation of potato starch silicated with silicic acid
PublikacjaApplication of microwave irradiation for the silication of granular potato starch with silicic acid, and the properties of silicated starch were investigated. Potato starch was esterified on 20 min microwave irradiation of starch with silicic acid, applying the power of 450 or 800Wand, for comparison, on 120 min convectional heating of the reagent blend at 100 ◦C. The degree of esterification and the reaction efficiency did not...
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Microwave-assisted synthesis of zinc derivatives of potato starch
PublikacjaZincatated potato starch was prepared in a solid-state, microwave-assisted reaction using generated in situ sodium tetrahydroxozincate [Na2Zn(OH)4]. For comparison, zincatation of starch was also carriedout on convectional heating. Depending on the irradiation conditions, the products of either mono- or crosslinking esterification were formed. Higher power applied at shorter exposition offered products ofmonoesterification, and...
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Zeolitic imidazolate framework (ZIF-8) modified cellulose acetate NF membranes for potential water treatment application
PublikacjaIn this study, cellulose acetate (CA)-based nanofiltration membranes, modified with zeolitic imidazole framework-8 (ZIF-8) particles, were prepared with various ZIF-8 contents (0, 0.1, 0.25, 0.5, 1 and 2 wt%), to obtain membranes with improved flux and filtration performance by combining advantages of CA polymer and ZIF-8 metal-organic frameworks. Removal efficiency studies were carried out with bovine serum albumin and two different...
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The effect of dehydration/rehydration of bacterial nanocellulose on its tensile strength and physicochemical properties
PublikacjaBacterial nanocellulose (BNC) is a natural biomaterial with a wide range of biomedical applications. BNC contains 99 % of water which makes it too thick to be used as a bioimplant material. The aim of the work was to determine the effect of the BNC dehydration followed by rehydration on its mechanical and physicochemical properties, in the context of the use of BNC as bio-prostheses in the cardiovascular system. Dehydration involved the...
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Chitin nanowhiskers from shrimp shell waste as green filler in acrylonitrile-butadiene rubber: Processing and performance properties
PublikacjaIn this work, chitin nanowhiskers with high crystallinity index were obtained from shrimp shells waste using acid hydrolysis method and then comprehensively characterized. Subsequently, the impact of chitin nanowhisker content on processing and performance of acrylonitrile-butadiene rubber based nanocomposites was evaluated. The results showed that the addition of chitin nanowhiskers increased tensile strength and tear strength...
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Effect of chemical structure on complexation efficiency of aromatic drugs with cyclodextrins: The example of dibenzazepine derivatives
PublikacjaIt is widely believed that the hydrophobic effect governs the binding of guest molecules to cyclodextrins (CDs). However, it is also known that high hydrophobicity of guest molecules does not always translate to the formation of stable inclusion complexes with CDs. Indeed, a plethora of other factors can play a role in the efficiency of guest–CD interactions, rendering structure-based prediction of the complexation efficiency with...
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Biomedical engineering of polysaccharide-based tissue adhesives: Recent advances and future direction
PublikacjaTissue adhesives have been widely used for preventing wound leaks, sever bleeding, as well as for enhancing drug delivery and biosensing. However, only a few among suggested platforms cover the circumstances required for high-adhesion strength and biocompatibility, without toxicity. Antibacterial properties, controllable degradation, encapsulation capacity, detectability by image-guided procedures and affordable price are also...
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Chitin and derivative chitosan-based structures — Preparation strategies aided by deep eutectic solvents: A review
PublikacjaThe high molecular weight of chitin, as a biopolymer, challenges its extraction due to its insolubility in the solvents. Also, chitosan, as the N-deacetylated form of chitin, can be employed as a primary material for different industries. The low mechanical stability and poor plasticity of chitosan films, as a result of incompatible interaction between chitosan and the used solvent, have limited its industrialization. Deep eutectic...
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A novel method of creating thermoplastic chitosan blends to produce cell scaffolds by FDM additive manufacturing
PublikacjaDue to its remarkable and promising biological and structural properties, chitosan has been widely studied in several potential applications in the biomedical sector. Attempts are being made to use this polymer and its properties in thermoplastics dedicated to 3D printing in FDM technology. However, chitosan can be processed only from acid solution, which limits its applications. The paper presents a new path for the production...
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Polysaccharide-based electroconductive hydrogels: Structure, properties and biomedical applications
PublikacjaArchitecting an appropriate platform for biomedical applications requires setting a balance between simplicity and complexity. Polysaccharides (PSAs) play essential roles in our life in food resources, structural materials, and energy storage capacitors. Moreover, the diversity and abundance of PSAs have made them an indispensable part of food ingredients and cosmetics. PSA-based hydrogels have been extensively reviewed in biomedical...
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Structural changes of bacterial cellulose due to incubation in conditions simulating human plasma in the presence of selected pathogens
PublikacjaBacterial nanocellulose (BNC) is a natural biomaterial with a wide range of medical applications. However, it cannot be used as a biological implant of the circulatory system without checking whether it is biodegradable under human plasma conditions. This work aimed to investigate the BNC biodegradation by selected pathogens under conditions simulating human plasma. The BNC was incubated in simulated biological fluids with or...