Добірка наукової літератури з теми "Β-cyclodextrin and chitosan"

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Статті в журналах з теми "Β-cyclodextrin and chitosan"

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Kontogiannidou, Eleni, Martina Ferrari, Asteria-Danai Deligianni, Nikolaos Bouropoulos, Dimitrios A. Andreadis, Milena Sorrenti, Laura Catenacci, et al. "In Vitro and Ex Vivo Evaluation of Tablets Containing Piroxicam-Cyclodextrin Complexes for Buccal Delivery." Pharmaceutics 11, no. 8 (August 8, 2019): 398. http://dx.doi.org/10.3390/pharmaceutics11080398.

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Анотація:
In the current study, the development of mucoadhesive tablets for buccal delivery of a non-steroidal anti-inflammatory drug was investigated. Binary complexes with piroxicam and cyclodextrins (β-cyclodextrin (β-CD), methylated-β-cyclodextrin (Me-β-CD), and hydroxypropyl-β-cyclodextrin (HP-β-CD)) were prepared by the co-evaporation method. All formulations were characterized by means of differential scanning calorimetry, infrared spectroscopy and powder X-ray diffractometry. Mucoadhesive tablets of binary systems were formulated by direct compression using chitosan as mucoadhesive polymer. The in vitro release profiles of tablets were conducted in simulated saliva and, the drug permeation studies, across porcine buccal mucosa. The results suggest that the rank order effect of cyclodextrins for the drug release was Me-β-CD > HP-β-CD > β-CD, whereas the ex vivo studies showed that the tablets containing chitosan significantly increased the transport of the drug compared to their free complexes. Finally, histological assessment revealed loss of the superficial cell layers, which might be attributed to the presence of cyclodextrins.
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Kozieł, Kinga, Jakub Łagiewka, Beata Girek, Agnieszka Folentarska, Tomasz Girek та Wojciech Ciesielski. "Synthesis of New Amino—β-Cyclodextrin Polymer, Cross-Linked with Pyromellitic Dianhydride and Their Use for the Synthesis of Polymeric Cyclodextrin Based Nanoparticles". Polymers 13, № 8 (19 квітня 2021): 1332. http://dx.doi.org/10.3390/polym13081332.

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New water soluble amino β-cyclodextrin-based polymer was synthesized by reaction between amino cyclodextrin derivatives and pyromellitic anhydride. This experiment presents amino derivatives, which were synthesized by attaching amino groups to β-cyclodextrins (β-CDs) used mono-6-azido-6-deoxy-β-cyclodextrin (β-CD-N3) and triphenylphosphine (Ph3P) in anhydrous N,N-dimethylformamide (DMF). An amino blocking reaction was conducted. The obtained polymer was purified by ultrafiltration. In addition, an attempt was made to create nanospheres by encapsulating the polymer with chitosan (CT) in an acidic condition. For the first time, nanospheres were obtained in the reaction between an amino β-cyclodextrin polymer and chitosan. Scanning electron microscopy (SEM). 1H NMR and ESI-MS methods for confirmation of reaction product and for structural characterization were employed. The differential scanning calorimetry (DSC) studies of polymers were also carried out.
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Li, Ruobao, Chunling Zhao, Weifen Zhang, Lihong Shi та Jinbao Tang. "Comparison study of chitosan/β-cyclodextrin and carboxymethyl chitosan/β-cyclodextrin microspheres". Wuhan University Journal of Natural Sciences 14, № 4 (12 липня 2009): 362–68. http://dx.doi.org/10.1007/s11859-009-0415-2.

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Li, Wei Hong, Jing Guan, Miao Lei Jing, Shu Jie Huang, Ji Min Wu, Zhi Hong Li, Xiu Dong You та Li Mei Hao. "Discussion on β-Cyclodextrin Grafting onto Chitosan Fiber Protected by Benzaldehyde". Applied Mechanics and Materials 152-154 (січень 2012): 244–49. http://dx.doi.org/10.4028/www.scientific.net/amm.152-154.244.

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Анотація:
In order to graft β-cyclodextrin onto chitosan fibers as more as possible, amino group of chitosan fibers should be protected by benzaldehyde firstly. Based on the similar structure of chitosan and cellulose fibers, different experimental programs were employed to discuss the possibility of β-cyclodextrin grafted onto chitosan fibers in the similar method. By infrared spectral and UV–visible spectroscopy analysis, the results showed although benzaldehyde could be grafted to chitosan fibers successfully to protect amino group, β-cyclodextrin could not be grafted further.
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Youwei, Yu, та Ren Yinzhe. "Grape Preservation Using Chitosan Combined withβ-Cyclodextrin". International Journal of Agronomy 2013 (2013): 1–8. http://dx.doi.org/10.1155/2013/209235.

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Анотація:
The effect of 1% chitosan combined with 2%β-cyclodextrin to the preservation of fresh grapes under ambient temperature was investigated. The results indicated that the hydrogen bond formed between the hydroxyl group ofβ-cyclodextrin and the amidogen or hydroxyl group of chitosan and the crystal form of chitosan was also changed when cyclodextrin was doped into chitosan coating. The compound coating could prolong the shelf life of grapes, maintain lower respiration rate and higher activities of superoxide dismutase, peroxidase, and catalase during storage time, and restrain weight loss and malonaldehyde content increase. Coating grapes with chitosan +β-cyclodextrin was a good method in postharvested grape preservation.
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Lv, Zhen, Fu Guang Lu, Lu Lu Fan, Hua Min Qiu та Chuan Nan Luo. "Study on Synthesis and Adsorption Properties of Chitosan Modified by DMF Grafted β-CD". Advanced Materials Research 306-307 (серпень 2011): 642–45. http://dx.doi.org/10.4028/www.scientific.net/amr.306-307.642.

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Анотація:
The synthesis chitosan modified by N,N-dimethylformamide(DMF) grafted β-CD (CTS), adsorption experiments of lanthanide ions, a new type water treatment agent, are discussed in this paper. First, the chitosan was modified by DMF, and then β-cyclodextrin (β-CD) was grafted onto chitosan skeleton by epoxy chloropropane. The effects of temperature, pH value, adsorption time on adsorption content were studied. The water treatment agent have a high lanthanide adsorption rate up to 98% compared to chitosan, b-CD and chitosan derivative bearing β-cyclodextrin.
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Zhou, Zhi Wu, Jing Song Wang, Qing Wei Guo та Zhen Cheng Xu. "Preparation of Magnetic Chitosan-β-Cyclodextrin Polymer and its Adsorption for Thallium (III) in Aqueous Solution". Advanced Materials Research 479-481 (лютий 2012): 1733–36. http://dx.doi.org/10.4028/www.scientific.net/amr.479-481.1733.

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Анотація:
Magnetic chitosan bonded β-cyclodextrin polymer was prepared, and its metal ion binding was studied using the batch static tests for thallium removal. The results indicated that magnetic chitosan-β-cyclodextrin polymer (MCS-CD) showed a high efficiency for the removal of thallium, the experiment data fitted well to the pseudo second-order kinetic model, the maximum adsorption capacity of 2.154mgg-1 was obtained according to the isothermal data.
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Suhail, Muhammad, Yu-Fang Shao, Quoc Lam Vu, and Pao-Chu Wu. "Designing of pH-Sensitive Hydrogels for Colon Targeted Drug Delivery; Characterization and In Vitro Evaluation." Gels 8, no. 3 (March 3, 2022): 155. http://dx.doi.org/10.3390/gels8030155.

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Анотація:
In the current research work, pH-sensitive hydrogels were prepared via a free radical polymerization technique for the targeted delivery of 5-aminosalicylic acid to the colon. Various proportions of chitosan, β-Cyclodextrin, and acrylic acid were cross-linked by ethylene glycol dimethacrylate. Ammonium persulfate was employed as an initiator. The development of a new polymeric network and the successful encapsulation of the drug were confirmed by Fourier transform infrared spectroscopy. Thermogravimetric analysis indicated high thermal stability of the hydrogel compared to pure chitosan and β-Cyclodextrin. A rough and hard surface was revealed by scanning electron microscopy. Similarly, the crystallinity of the chitosan, β-Cyclodextrin, and fabricated hydrogel was evaluated using powder X-ray diffraction. The swelling and drug release studies were performed in both acidic and basic medium (pH 1.2 and 7.4, respectively) at 37 °C. High swelling and drug release was observed at pH 7.4 as compared to pH 1.2. The increased incorporation of chitosan, β-Cyclodextrin, and acrylic acid led to an increase in porosity, swelling, loading, drug release, and gel fraction of the hydrogel, whereas a decrease in sol fraction was observed. Thus, we can conclude from the results that a developed pH-sensitive network of hydrogel could be employed as a promising carrier for targeted drug delivery systems.
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Zhang, Yan, Hui Zhang, Fang Wang та Li-Xia Wang. "Preparation and Properties of Ginger Essential Oil β-Cyclodextrin/Chitosan Inclusion Complexes". Coatings 8, № 9 (29 серпня 2018): 305. http://dx.doi.org/10.3390/coatings8090305.

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Анотація:
The ginger essential oil/β-cyclodextrin (GEO/β-CD) composite, ginger essential oil/β-cyclodextrin/chitosan (GEO/β-CD/CTS) particles and ginger essential oil/β-cyclodextrin/chitosan (GEO/β-CD/CTS) microsphere were prepared with the methods of inclusion, ionic gelation and spray drying. Their properties were studied by using scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermo-gravimetry analysis (TGA), Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD). The results showed that the particle size of GEO/β-CD composite was smaller than that of β-CD and GEO/β-CD/CTS particles were loose and porous, while the microsphere obtained by spray drying had certain cohesiveness and small particle size. Besides, results also indicated that β-CD/CTS could modify properties and improve the thermal stability of GEO, which would improve its application value in food and medical industries.
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Petitjean, Max, Florian Aussant, Ainara Vergara та José Ramón Isasi. "Solventless Crosslinking of Chitosan, Xanthan, and Locust Bean Gum Networks Functionalized with β-Cyclodextrin". Gels 6, № 4 (15 грудня 2020): 51. http://dx.doi.org/10.3390/gels6040051.

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Анотація:
The incorporation of cyclodextrins into polymeric crosslinked gels of hydrophilic nature can be useful for promoting the sorption of hydrophobic molecules and/or modulating the release of active principles. The covalent addition of these excipients to the matrix integrates their solubilizing effect that can contribute to increase the capacity of retention of hydrophobic substances. In this study, three diverse polysaccharides, chitosan, xanthan gum, and locust bean gum, were crosslinked with or without β-cyclodextrin, using citric acid in different ratios, to create hydrogel matrices. Through a green synthetic path, the efficient production of soluble and insoluble (hydrogel) networks functionalized with β-cyclodextrin was achieved by means of a solventless procedure. The characterization of their chemical composition, swelling in water, and their sorption and release behavior were also carried out in this work.
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Дисертації з теми "Β-cyclodextrin and chitosan"

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Fusteș-Dămoc, Iolanda. "Matériaux polymères durables synthétisés à base d'oligo- et de polysaccharides." Electronic Thesis or Diss., Université Côte d'Azur, 2023. http://www.theses.fr/2023COAZ4076.

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Анотація:
La durabilité des matériaux est leur capacité à résister dans le temps à l'influence de divers facteurs tels que la température, l'humidité, la rupture, tout en conservant leurs caractéristiques.Les matériaux polymères durables sont la solution contre la pollution de l'environnement. Dans ce contexte, le développement de matériaux polymères durables basés sur des composés biodégradables, que l'on trouve en abondance dans la nature, même à partir de déchets industriels, et qui ont également un faible prix de revient, est une alternative possible aux matériaux basés sur des composés fossiles, qui sont toxiques. En même temps, l'utilisation d'un minimum de produits chimiques est un atout pour la production à grande échelle par les industries. En outre, l'obtention de propriétés avantageuses dans ces conditions, adaptées à certains types d'applications, ajoute de la valeur, ce qui recommande leur utilisation par rapport aux matériaux toxiques.Les oligo- et polysaccharides constituent une matière première appropriée qui pourrait être exploitée dans la conception de matériaux polymères durables. Leur utilisation a déjà suscité un réel intérêt de la part des chercheurs, mais leur application au niveau industriel se heurte à un certain nombre de difficultés : des procédés technologiques inadaptés et de la consommation élevée de solvants et de produits chimiques au coût élevé de l'obtention, du recyclage et de la réutilisation des matériaux, conformément à une économie circulaire, essentielle dans l'approche de la protection de l'environnement. Cette économie circulaire consiste à prolonger le cycle de vie des matériaux en réduisant les déchets. Elle privilégie la réparation, la réutilisation et le recyclage des matériaux le plus longtemps possible. Cette thèse de doctorat présente les résultats obtenus par la synthèse, la caractérisation et le test de matériaux durables à base d'oligo- et de polysaccharides.L'objectif global de la thèse de doctorat est de développer des matériaux durables qui intègrent et exploitent des composés non toxiques, renouvelables, respectueux de l'environnement, bon marché et abondants dans la nature tels que les oligo- et polysaccharides dans une économie circulaire.Les principaux axes de recherche développés dans la thèse sont:- Valorisation de la β-cyclodextrine, de la catégorie des oligosaccharides, et du chitosane, de la catégorie des polysaccharides, dans des systèmes de matériaux durables;- Développement de tels matériaux durables, en utilisant également un minimum d'étapes et un nombre réduit de composés et de solvants respectueux de l'environnement;- Utilisation, en particulier, du chitosane sous forme solide (poudre) pour optimiser les propriétés mécaniques et thermiques des systèmes;- Obtention de propriétés matérielles améliorées par l'introduction d'oligo- et de polysaccharides, par rapport aux systèmes de référence, pour les systèmes à base de chitosane: amélioration des caractéristiques mécaniques et thermiques, et pour les systèmes à base de β-cyclodextrine: optimisation de l'adsorption de divers polluants tels que les antibiotiques, les colorants organiques, les métaux lourds;- Augmenter le potentiel d'application des matériaux dans divers domaines tels que le biomédical, l'emballage alimentaire, les revêtements époxy, l'aérospatiale, en raison des avantages que possèdent les oligo- et les polysaccharides ;- Vérifier la recyclabilité des nanomatériaux à base de β-cyclodextrine afin d'améliorer la durabilité des matériaux
The durability of materials is their ability to withstand over time the influence of various factors such as temperature, humidity and breakage while maintaining their characteristics.Durable polymer materials are the solution to environmental pollution. In this context, the development of sustainable polymer materials based on biodegradable compounds, which are abundant in nature, even from industrial waste, and which also have a low cost price, is a possible alternative to materials based on fossil compounds, which are toxic. At the same time, the use of minimal chemicals is an advantage for large-scale production by industries. In addition, obtaining advantageous properties under these conditions, tailored to certain types of applications, brings added value, which recommends their use over toxic materials.Oligo- and polysaccharides represent a suitable raw material that could be exploited in the design of durable polymeric materials. Their use has already aroused real interest among researchers, but their industrial application faces a number of difficulties: from inadequate technological processes and high consumption of solvents and chemicals to the high costs of obtaining, recycling and reusing materials, in line with a circular economy, which is essential in addressing environmental protection. This circular economy is about extending the life cycle of materials by reducing waste. by promoting the repair, reuse and recycling of materials for as long as possible. This PhD thesis presents the results obtained from the synthesis, characterisation and testing of sustainable oligo- and polysaccharide-based materials.The overall objective of the PhD thesis is to develop durable materials that incorporate and exploit non-toxic, renewable, environmentally friendly, cheap and naturally abundant compounds such as oligo- and polysaccharides in a circular economy.The main research directions developed in the thesis are:- Valorisation of β-cyclodextrin, from the oligosaccharide category, and chitosan, from the polysaccharide category, in sustainable material systems;- Development of such sustainable materials using a minimum number of steps and a reduced number of compounds and solvents;- The use, in particular, of chitosan in solid (powder) form to optimise the mechanical and thermal properties of the systems;- Achieving improved mechanical and thermal properties of the materials by introducing oligo- and polysaccharides, compared to reference systems, for chitosan-based systems, and for β-cyclodextrin-based systems: optimised adsorption of various pollutants such as antibiotics, organic dyes, heavy metals;- increased application potential of materials in various fields such as biomedical, food packaging, epoxy coatings, aerospace, due to the advantages of oligo- and polysaccharides;- Testing the recyclability of β-cyclodextrin-based nanomaterials to improve material durability
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"Synthesis of β-cyclodextrin and chitosan-based copolymers for the removal of naphthenic acids". Thesis, 2013. http://hdl.handle.net/10388/ETD-2013-03-1000.

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Анотація:
Naphthenic acids (NAs) are a group of carboxylic acids that are found in hydrocarbon deposits such as the oil sands bitumen. These compounds are a well-known corrosive agent and a toxic component in the oil sands process water (OSPW). Due to Alberta’s zero discharge policy, OSPW cannot be released and must be stored until toxic components like NAs are remediated. One technique that has shown potential is to physically adsorb NAs onto a copolymer generated from economical biomaterials. Therefore, the project can be divided into three sections: 1) Synthesis of β-cyclodextrin (β-CD) copolymer for the sorption of p-nitrophenol (PNP); 2) Synthesis of chitosan-based copolymers (Chi-Glu) for the sorption of PNP; 3) Sorption of carboxylates and NAs using Chi-Glu copolymers. PNP sorption was used as a probe to understand the physicochemical properties of the copolymers. In the first section, β-CD was reacted with sebacoyl chloride (SCl) and terephthaloyl chloride (TCl) at various mole ratios. Characterization was done using Fourier Transform Infrared Spectroscopy (FT-IR), thermogravimetric analysis (TGA), 1H NMR spectroscopy (1H NMR), elemental analysis (CHN), and nitrogen porosimetry. Copolymers synthesized at mole ratios of β-CD to SCl from 1:1 to 1:3 were hydrolyzed at acidic and basic conditions. Therefore, sorption studies were not done at these ratios. The same occurred for 1:1 to 1:3 TCl copolymers. Sorption studies with PNP at pH 4.6 demonstrated enhanced sorption capacity when comparing with a standard: granular activated carbon (GAC). The sorption capacity, Qm (mmol/g), ordered from largest to smallest is 1:9 SCl>1:9 TCl>1:6 SCl> GAC> 1:6 TCl. Chi-Glu copolymers were synthesized by cross-linking glutaraldehyde with pristine chitosan. A systematic study on the effects reaction conditions have on the sorption capacity of the materials was done. Three conditions were changed: pH, temperature, and mole ratios. Chi-Glu copolymers were synthesized at various chitosan to glutaraldehyde mole ratios (1:400, 1:700, 1:1000). Sufficient time was allowed for the aging process. Characterization was done using TGA, FT-IR, CHN, and nitrogen porosimetry. Sorption study with PNP were done at pH = 7.0 and 9.0. At pH = 7.0 sorption capacity appears to correlate to the quantity of homo-polymerized glutaraldehyde: 1:700>1:1000>1:400. While at pH = 9.0, the sorption capacity is inversely proportional to the degree of crosslinking: 1:400>1:700>1:1000. By increasing the pH at the shrinkage phase, PNP was weakly bound onto the Chi-Glu copolymer. Varying temperature before gelation caused a decrease in the sorption capacity with PNP. Sorption studies involving carboxylates and NAs were done at pH = 9.0 at ambient temperature using Chi-Glu copolymers (1:400, 1:700, and 1:1000) and chitosan. Three carboxylates were chosen to reflect the diverse components in NAs. Varying degrees of cyclization (Z = 0, -2, -4) and lipophilic surface area were the main criteria for carboxylates. The sorption capacity depended mainly on the lipophilic surface area (LSA) with sorption capacity highest for 2-hexyldecanoic acid (S1) which has the largest LSA and lowest for, trans-4-pentylcyclohexanecarboxylic acid (S2) and dicyclohexylacetic acid (S3). Unfortunately, cross-linking with glutaraldehyde does not enhance sorption as pristine chitosan retained a higher sorption capacity compared to Chi-Glu copolymers. Acros and Fluka NAs were chosen for sorption and no significant sorption was recorded for any copolymers. Problems involving the micellization process can explain the lack of sorption.
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Ciou, Yi-Jium, та 邱儀郡. "Preparation and Application of (Poly methyl methacrylate/ Carboxymethyl-β-cyclodextrin /Chitosan) nanofibers by electrospinning". Thesis, 2015. http://ndltd.ncl.edu.tw/handle/nffs64.

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Анотація:
碩士
國立雲林科技大學
化學工程與材料工程系
103
The purpose of this study was to use of three different properties of the polymer materials(1)Poly(methyl-methacrylate),referred to as PMMA,(2)Carboxymethyl-β-cyclodextrin, referred to as CM- β-CD and (3) Chitosan, referred to as CS, solvent selection formic acid can be formulated PMMA / CM – β – CD / Chitosan solution, and it can produce nanoscale fibers for application by electrospinning . At first, the basic properties of the PMMA / CM – β – CD / Chitosan solution was observed with conductivity meter, observed with increasing PMMA content, and found the trend of decrease in conductivity of the solution. The electrospinning conditions of manufacturing (including: the flow rate of the propeller, the needle distance, voltage, ambient temperature and the fiber collection methods, etc ...) to the effect of different ratios of PMMA / CM – β – CD / Chitosan nanoscale fibers. The best conditions of manufacturing were the output voltage of 23kv, solution flow rate 0.030 ml/min, collection fiber distance of 15 cm and ambient temperature 30℃. The ratio of the best composite of polymer solution were dvided into three groups to produce nanoscale fibers, and prepared individually for different applications(1) Fiber barbed wire (2) Semi-finished fiber masks (3) Antibacterial fiber fabrics. The physical analysis are using field electron microscope (FE-SEM), Fourier transform infrared spectroscopy (FTIR), the contact angle measuring instrument (CA), X-ray diffraction analyzer (XRD) and nitrogen isothermal adsorption / desorption analyzer (BET) detection surface patterns fibers, functional groups, hydrophobicity, crystallinity analysis, hole size distribution and specific surface area and void volume. Finally, the results show that (1) Fiber barbed wire: the maximum amount of adsorption qemax = 124.90mg/g for the proposed second-order kinetic adsorption model, and the material has a mesoporous structure were encapulsated the heavy metal copper ions to achieve the effect of adsorption . Thus, it also has an internal diffusion model. (2) Semi-finished fiber masks: conform to disposable dust masks D1 grade and the same time both medical masks - bacterial filter function. (3) Antibacterial fiber fabrics: Medical antibacterial AATCC 100 test results prove that fiber is an antimicrobial can be applied to the fabric of the medical aspect.
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Huang, Shih-Pin, та 黃士繽. "Preparation of chitosan/β-cyclodextrin complex particles and their effect on the stability of astaxanthin microemulsion". Thesis, 2008. http://ndltd.ncl.edu.tw/handle/59866596546318178166.

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Анотація:
碩士
國立臺灣海洋大學
食品科學系
96
Astaxanthin (3,3’-dihydroxy-β-β’-carotene-4-4’-dione) has been gaining widespread popularity as a dietary supplement due to its powerful antioxidant properties. Similar to other carotenoids, astaxanthin is a highly unsaturated molecule and thus, can easily be degraded by thermal or oxidative processes during the manufacture and storage of foods. This may cause the loss of their nutritive and desirable biological properties. Cyclodextrins (CDs) are composed of α-1,4-linked glucopyranose subunits, these apolar internal cavities can form complexes with and solubilize many normally water-insoluble compounds. The synthesised chitosan/β-cyclodextrin polymer exhibits the characteristics of a possible drug delivery system with some inclusion properties from β-cyclodextrin. β-cyclodextrin was successfully grafted onto a chitosan chain polymer with a cyclodextrin grafting yield of 7 %. The astaxanthin microemulsion with 95 wt % aqueous phase with added 0.05 % chitosan/β-cyclodextrin has the highest astaxanthin solubility. For the astaxanthin microemulsion with 40 wt % aqueous phase, the group with added chitosan/β-cyclodextrin has the highest efficacy of scavenging ABTS+. The flow behavior of astaxanthin microemulsion is a Newtonian fluid. The astaxanthin microemulsion makes good absorbance at UVC zone (280-200 nm). The astaxanthin microemulsion of 40 wt % aqueous phase is more stable than the group with added the carriers under UV radiation. The 40 wt % aqueous phase composition makes astaxanthin more stable than T64 and the group with added the carriers provides more thermal protection for astaxanthin. The astaxanthin microemulsion with added chitosan/β-cyclodextrin has the potential to increase the solubility of astaxanthin and provides more protection for astaxanthin.
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Utzeri, Gianluca. "Desenvolvimento de biogéis de pectina e quitosano para a sorção de Cymoxanil." Master's thesis, 2018. http://hdl.handle.net/10316/86662.

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Анотація:
Dissertação de Mestrado em Química apresentada à Faculdade de Ciências e Tecnologia
O termo pesticida compreende uma ampla gama de produtos para a proteção das plantas (PPPs) e biocidas que podem apresentar diferentes níveis de persistência e toxicidade, afetando o ambiente e os seres vivos, dependendo de muitos fatores e da forma de contato. Consequentemente, a sua remoção do ambiente e das águas superficiais e subterrâneas tem grande importância e desde 1970 novos materiais e tecnologias foram desenvolvidos para este objetivo. Neste estudo, foram sintetizados hidrogéis à base de quitosano (QT) com pectina (PT) e pectina funcionalizada com β-ciclodextrina (β-PT), por coacervação complexa em sistema de emulsão óleo/água. A funcionalização da pectina obteve-se por reação de transesterificação em ambiente ácido e o produto foi caraterizado usando técnicas como a ressonância magnética nuclear protónica (1H-RMN) e a espetroscopia infravermelho por reflexão total atenuada (IR-ATR). Os hidrogéis, além da caraterização por IR-ATR, foram avaliados por análise termogravimétrica (TGA) e microscopia eletrónica de varrimento (SEM). As três técnicas foram efetuadas antes e após contato com o Cymoxanil (CYM) em solução aquosa por 24 h. As caraterísticas mecânicas dos dois complexos foram determinadas por análise reológica. A interação entre os hidrogéis e o Cymoxanil foi avaliada através estudo das isotérmicas de sorção a 12 e 24 horas. A quantificação da concentração de Cymoxanil em solução aquosa determinou-se por análise HPLC-DAD. Dos valores de eficiência de remoção é evidente um aumento da capacidade de remoção em presença de β-ciclodextrina (CD), todavia, para ambos os complexos, observa-se uma forte dependência da massa de hidrogel seco utilizado.
The term pesticide comprises a wide range of plant protection products (PPPs) and biocides. It may present different levels of persistence and toxicity with environment pollution and affecting human and animal life by direct or indirect contact. Consequently, their removal from environment and from surface and groundwater is of great importance since1970 and new materials and technologies have been developed for this purpose. In this study, chitosan-based (QT) hydrogels with pectin (PT) and β-Cyclodextrin functionalised pectin (β-PT) were synthesized by complex coacervation in oil/water emulsion system. The functionalization of pectin was obtained by transesterification in acidic environment and the product was characterized using techniques such as nuclear magnetic resonance (1H-NMR) and by attenuated total reflection infrared spectroscopy (IR-ATR). The hydrogels characterization, besides IR-ATR analysis, was evaluated by thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The three techniques were performed before and after interaction with Cymoxanil (CYM) aqueous solution for 24 h. The mechanical properties of the two complexes were determined by rheological analysis. The interaction between the hydrogels and Cymoxanil was evaluated through determination of sorption isotherms at 12 and 24 hours. Quantification of the concentration of Cymoxanil in aqueous solution was determined by HPLC-DAD analysis. From the removal efficiency values an increase in the removal capacity in presence of β-Cyclodextrin (CD) is evident, for both complexes, a strong dependence on the dry hydrogels used mass is observed.
Outro - Este trabalho é financiado por Fundos Nacionais através da FCT - Fundação para a Ciência e a Tecnologia no âmbito do projeto WaterJPI/0006/2016.
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Thomas, Ananya. "Thermal and calorimetric evaluations of some bio-inspired fire-resistant coatings for ligno-cellulosic materials." Thesis, 2020. https://vuir.vu.edu.au/40844/.

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Through the current project, we have investigated the passive fire protection efficiency of some bio-inspired substrates, which included: β-cyclodextrin, dextran, potato starch, agar agar, tamarind, chitosan, rice bran and fish gelatin. In an attempt to enhance the passive fire protection attributes of these substrates, we prepared formulations of these with both inorganic and organic compounds, the latter included some phosphorus-containing compounds with the phosphorus atom in different chemical environments and oxidation states. Here we have also explored both the reactive and additive strategies. The degrees of functionalization were primarily gauged from inductively-coupled plasma/optical emission spectroscopy (ICP-OES), 31P solid-state Nuclear Magnetic Resonance Spectroscopy (NMR). We also chose several thermal and calorimetric techniques for evaluating the efficacies of such formulations, such as: thermo-gravimetric analysis (TGA), pyrolysis combustion flow calorimetry (PCFC), a proprietary ignition propensity test and cone calorimetry. In addition, with a view to deciphering the elements of condensed phase mechanism, we carried out an estimation of the extents of phosphorus retention in the char residues (using ICP-OES) and chemical nature of the char residues (via solid-state NMR and Raman spectroscopies) that were obtained through the cone calorimetric runs. The unmodified counterparts were also subjected to the same set of analyses with a view to serving as controls. We also endeavoured to analyse the gaseous volatile fragments emanating from some of the additives using, either by employing gas chromatography/mass spectrometry (GC/MS), or pyrolysis-GC/MS, technique. Phosphorus analyses, primarily, through ICP-OES on the recovered samples showed different degrees of incorporation. Such observations were verified through solid-state 31P NMR spectroscopy. The thermograms of the modified substrates were noticeably different from the unmodified counterparts, both in terms of the general profiles and the amounts of char residues produced. Such observations correlated well with the relevant parameters obtained through the PCFC runs. Furthermore, we have carried out a detailed kinetic analyses of the thermograms of the unmodified substrates, obtained at different heating rates, using the Flynn Wall Ozawa (FWO) method, and through a proprietary software developed by our research group (SB method). We have also endeavoured to seek correlations, if any, among the various empirical parameters that were collated through the different test methods. Overall, the modified systems containing phosphorus were found to be less combustible than the parent substrates, and thus can be considered as promising base matrices for environmentally-benign fire resistant coatings. With a view to understanding the overall flammability profiles, optionally, in some of the formulations, initially we screened them through an ignitability propensity test that was developed in our laboratories. This was followed by cone calorimetric measurements on Radiata Pine plaques, particularly, coated with potato starch, chitosan, chitin, rice bran and fish gelatin. The results from the cone tests indicated that formulations based on fish gelatin endowed with the best fire protection property, followed by chitosan, whereas potato starch and rice bran seem to be ineffective as fire proofing agents.
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Частини книг з теми "Β-cyclodextrin and chitosan"

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Zhao, Feiping, and Mika Sillanpää. "Cross-linked chitosan and β-cyclodextrin as functional adsorbents in water treatment." In Advanced Water Treatment, 161–264. Elsevier, 2020. http://dx.doi.org/10.1016/b978-0-12-819216-0.00003-5.

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Bejaoui, Marouene, Hanen Oueslati, and Haykel Galai. "Ternary Solid Dispersion Strategy for Solubility Enhancement of Poorly Soluble Drugs by Co-Milling Technique." In Chitin and Chitosan - Physicochemical Properties and Industrial Applications [Working Title]. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.95518.

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Amorphous ternary solid dispersion has become one of the strategies commonly used for improving the solubility and bioavailability of poorly water soluble drugs. Such multicomponent solid dispersion can be obtained by different techniques, this chapter provides an overview of ternary solid dispersion by co-milling method from the perspectives of physico-chemical characteristics in vitro and in vivo performance. A considerable improvement of solubility was obtained for many active pharmaceutical ingredients (e.g., Ibuprofen, Probucol, Gliclazid, Fenofibrate, Ibrutinib and Naproxen) and this was correlated to the synergy of multiple factors (hydrophilicity enhancement, particle size reduction, drug-carrier interactions, anti-plasticizing effect and complexation efficiency). This enhanced pharmacokinetic properties and bioavailability of these drug molecules (1.49 to 15-folds increase in plasma drug concentration). A particular focus was accorded to compare the ternary and binary system including Ibuprofen and highlighting the contribution of thermal and spectral characterization techniques. The addition of polyvinylpyrrolidone (PVP K30), a low molecular weight molecule, into the binary solid dispersion (Ibuprofen/β-cyclodextrin), leads to a 1.5–2 folds increase in the drug intrinsic dissolution rate only after 10 min. This resulted from physical stabilization of amorphous Ibuprofen by reducing its molecular mobility and inhibiting its recristallization even under stress conditions (75% RH and T = 40°C for six months).
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Тези доповідей конференцій з теми "Β-cyclodextrin and chitosan"

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Lema, Isabel, Francisco J. Otero-Espinar, Rubén Varela-Fernández, Xurxo García-Otero, Victoria Díaz-Tomé та Miguel González-Barcia. "Design, preparation, and characterization of lactoferrin-loaded sulfobutylether-β-cyclodextrin/chitosan nanoparticles as a therapeutic alternative for keratoconus treatment". У The 1st International Electronic Conference on Pharmaceutics. Basel, Switzerland: MDPI, 2020. http://dx.doi.org/10.3390/iecp2020-08793.

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