Journal articles: 'Carbohydrates polymer'

1

Bowen, P. T., and T. M. Keinath. "Sludge Conditioning: Effects of Sludge Biochemical Composition." Water Science and Technology 17, no. 4-5 (April 1, 1985): 505–15. http://dx.doi.org/10.2166/wst.1985.0155.

Full text

Abstract:

Variations in response of three different sludges to conditioning with organic polyelectrolytes were evaluated with respect to the carbohydrate, protein and lipid content of the sludges. These biochemicals comprise the surfaces of most sludges. The difference in the concentration of these compounds is intrinsic to the sludge type. Polymer Index (PI) , a measure of minimum polymer dose required to achieve maximum dewaterability, was statistically related to each of the three components. Carbohydrate content correlated most strongly with PI. As carbohydrate content increases, PI was found to decrease indicating better polymer performance. Biopolymers, which are composed mainly of carbohydrates may surround the cells forming a highly reactive surface. These exocellular materials also promote bioflocculation. Both actions result in a lower polymer requirement for destabilizing the sludge. Protein and lipid were not observed to have strong correlation with PI. Cellular surfaces and structures are composed of these components. The low correlation indicates these components are less favored than carbohydrates for polymer interaction.

APA, Harvard, Vancouver, ISO, and other styles

2

Krishnaveni Manubolu, Sreenivasulu Munna, and Chandrasekhar Kothapalli Bonnoth. "A Study on Extraction and Characterization of Vigna mungo Polymer." International Journal of Research in Pharmaceutical Sciences 12, no. 3 (July 1, 2021): 1870–78. http://dx.doi.org/10.26452/ijrps.v12i3.4787.

Full text

Abstract:

The aim of work is to extract and characterize the Vigna mungo polymer solvent using acetone and ethanol. Natural polymers contribution towards formulation of dosage forms is appreciable as they are biocompatible, biodegradable and safe. So extraction and characterization of Vigna mungo polymer helps in the interaction studies of preformulation. In this present study, various physicochemical characters like phytochemical screening, viscosity, particle size analysis, and flow characteristics were determined. Further characterization performed using FTIR and XRD. Vigna mungo polymer obtained using acetone was taken into further studies of evaluation because of more product yield and less particle size. FTIR results revealed existence of carbohydrate nature. X-ray diffractogram presented degree of crystallinity 26.4%. And phytochemical screening of the extracted polymer indicated presence of mucilage and carbohydrates using ruthenium red and molisch's test. Statistical analysis of data was performed using two way ANOVA using Graphpad prism 5 software was used to compare Vigna mungo polymer extracted using acetone and ethanol. Physicochemical parameters experimental data found to be statistical significance two way ANOVA (P < 0.05).

APA, Harvard, Vancouver, ISO, and other styles

3

Kerzner, B., H. R. Sloan, H. J. McClung, C. C. Chidi, A. H. Ailabouni, and C. Seckel. "Absorption of glucose polymers from canine jejunum deprived of pancreatic amylase." American Journal of Physiology-Gastrointestinal and Liver Physiology 250, no. 6 (June 1, 1986): G824—G829. http://dx.doi.org/10.1152/ajpgi.1986.250.6.g824.

Full text

Abstract:

We evaluated the absorption of glucose polymers in canine jejunal Thiry-Vella fistulas proven to be free of pancreatic amylase. Medium-length oligomers with degrees of polymerization of 6 through 10 glucose units (DP 6–10) and long-chain material (DPavg23) were isolated from a cornstarch hydrolysate. We perfused 90, 180, and 360 mg/dl solutions of glucose, DP 6–10, and DPavg23 at 0.4, 1.9, and 3.4 ml/min. At all perfusion rates carbohydrate absorption decreased as the chain length of the oligomers increased, and these differences persisted even at the slowest perfusion rate employed. In two additional animals the fistulas were perfused at 3.4 ml/min with the three test carbohydrates at concentrations of 90, 180, 225, 270, 315, 360, 405, and 450 mg/dl. At this flow rate, the assimilative process of DP 6–10 and the long-chain fraction appeared to be saturated at carbohydrate concentrations above 360 mg/dl, whereas the absorption of glucose was linearly related to concentration throughout the range studied. With both groups of polymers, the fluid emerging from the fistula was virtually free of glucose, a finding that suggests that polymer digestion, not glucose absorption, is the rate-limiting step for polymer assimilation.

APA, Harvard, Vancouver, ISO, and other styles

4

Flo, Trude H., Liv Ryan, Lars Kilaas, Gudmund Skjåk-Bræk, Robin R. Ingalls, Anders Sundan, Douglas T. Golenbock, and Terje Espevik. "Involvement of CD14 and β2-Integrins in Activating Cells with Soluble and Particulate Lipopolysaccharides and Mannuronic Acid Polymers." Infection and Immunity 68, no. 12 (December 1, 2000): 6770–76. http://dx.doi.org/10.1128/iai.68.12.6770-6776.2000.

Full text

Abstract:

ABSTRACT Lipopolysaccharide (LPS) and related bacterial products can be recognized by host inflammatory cells in a particulate, bacterium-bound form, as well as in various soluble, released forms. In the present study we have compared the mechanisms used by LPS, detoxified LPS (DLPS), and mannuronic acid polymers (M-polymers), in solution or covalently linked to particles, in stimulating monocytes to tumor necrosis factor (TNF) production. The addition of recombinant LPS binding protein (LBP) and/or soluble CD14 (sCD14) enhanced the production of TNF from monocytes stimulated with soluble LPS, DLPS, or M-polymer, but did not affect the response to M-polymer or DLPS attached to particles. Treatment of monocytes with antibody to CD14, CD18, or CD11b showed that CD14, but not CR3 (CD11b/CD18), mediated monocyte TNF production in response to the soluble antigens. In contrast, anti-CD14, anti-CD11b and anti-CD18 monoclonal antibodies all inhibited the response to the particulate stimuli. On the other hand, B975, a synthetic analog of Rhodobacter capsulatus lipid A, completely abrogated the monocyte TNF response induced by LPS but did not affect the TNF induction by DLPS or M-polymer, either in soluble or particulate forms. These data demonstrate that the engagement of immune receptors by bacterial products such as LPS, DLPS, and M-polymer is dependent upon the presentation form of their constituent carbohydrates, and that factors such as aggregation state, acylation, carbohydrate chain length, and solid versus liquid phase of bacterial ligands influence the mechanisms used by cells in mediating proinflammatory responses.

APA, Harvard, Vancouver, ISO, and other styles

5

Tan, Jin, Chenguang Wang, Qi Zhang, and Longlong Ma. "Synthesis and Characterization of Furans and Levulinates Polymers: Derived from Cellulosic Carbohydrates via Aldol Condensation." E3S Web of Conferences 53 (2018): 03011. http://dx.doi.org/10.1051/e3sconf/20185303011.

Full text

Abstract:

Aldol condensation between furans and levulinates shows a selective route for the polymers production. In this work, the influences of mole ratio between furans and levulinates as well as substrate species on the formation of polymers structure were investigated. The characterization of gel permeation chromatography and 13C nuclear magnetic resonance to the synthesized polymers suggested that the mole ratio between furans and levulinates, and substrate species exhibited a great effect on the structure of polymers. Higher mole ratios between furans and levulinates resulted in the aggravated polymerization. EMF-EL polymers showed larger molecular weight distribution compared with FFA-EL/LA polymers. This investigation further provides other key factors to the decision of polymer structure.

APA, Harvard, Vancouver, ISO, and other styles

6

Ribeiro, Jessica P. M., Patrícia V. Mendonça, Jorge F. J. Coelho, Krzysztof Matyjaszewski, and Arménio C. Serra. "Glycopolymer Brushes by Reversible Deactivation Radical Polymerization: Preparation, Applications, and Future Challenges." Polymers 12, no. 6 (June 1, 2020): 1268. http://dx.doi.org/10.3390/polym12061268.

Full text

Abstract:

The cellular surface contains specific proteins, also known as lectins, that are carbohydrates receptors involved in different biological events, such as cell–cell adhesion, cell recognition and cell differentiation. The synthesis of well-defined polymers containing carbohydrate units, known as glycopolymers, by reversible deactivation radical polymerization (RDRP) methods allows the development of tailor-made materials with high affinity for lectins because of their multivalent interaction. These polymers are promising candidates for the biomedical field, namely as novel diagnostic disease markers, biosensors, or carriers for tumor-targeted therapy. Although linear glycopolymers are extensively studied for lectin recognition, branched glycopolymeric structures, such as polymer brushes can establish stronger interactions with lectins. This specific glycopolymer topology can be synthesized in a bottlebrush form or grafted to/from surfaces by using RDRP methods, allowing a precise control over molecular weight, grafting density, and brush thickness. Here, the preparation and application of glycopolymer brushes is critically discussed and future research directions on this topic are suggested.

APA, Harvard, Vancouver, ISO, and other styles

7

Motoyanagi, Jin, Minh Nguyen, Tomonari Tanaka, and Masahiko Minoda. "Protecting Group-Free Synthesis of Glycopolymer-Type Amphiphilic Macromonomers and Their Use for the Preparation of Carbohydrate-Decorated Polymer Particles." Biomolecules 9, no. 2 (February 19, 2019): 72. http://dx.doi.org/10.3390/biom9020072.

Full text

Abstract:

Polymer particles modified with carbohydrates on their surfaces are of significant interest, because their specific recognition abilities to biomolecules are valuable for developing promising materials in biomedical fields. Carbohydrate-decorated core-shell polymer particles are expected to be efficiently prepared by dispersion polymerization using a glycopolymer-based amphiphilic macromonomer as both a polymeric steric stabilizer and a monomer. To create glycopolymer-type macromonomers, we propose a new strategy combining living cationic polymerization of an alkynyl-functionalized vinyl ether (VE), and the click reaction for the preparation of glycopolymers having a polymerizable terminal group, and investigate their dispersion copolymerization with styrene for generating carbohydrate-decorated polymer particles. This study deals with (i) the synthesis of block copolymer-type amphiphilic macromonomers bearing a methacryloyl group at the α-terminus, and pendant alkynyl groups by living cationic polymerization of alkynyl-substituted VE (VEEP), (ii) the derivatization of maltose-carrying macromonomers by click chemistry of the pendant alkynyl groups of the precursor macromonomers with maltosyl azide without any protecting/deprotecting processes, and (iii) the preparation of maltose-decorated (Mal-decorated) polymer particles through the dispersion copolymerization of glycopolymer-type macromonomers with styrene in polar media. Moreover, this study concerns the specific interactions of the resultant polymer particles with the lectin concanavalin A (Con A).

APA, Harvard, Vancouver, ISO, and other styles

8

Massicotte, D., F. Peronnet, G. Brisson, K. Bakkouch, and C. Hillaire-Marcel. "Oxidation of a glucose polymer during exercise: comparison with glucose and fructose." Journal of Applied Physiology 66, no. 1 (January 1, 1989): 179–83. http://dx.doi.org/10.1152/jappl.1989.66.1.179.

Full text

Abstract:

The purpose of this study was to compare the oxidation of 13C-labeled glucose, fructose, and glucose polymer ingested (1.33 g.kg-1 in 19 ml.kg-1 water) during cycle exercise (120 min, 53 +/- 2% maximal O2 uptake) in six healthy male subjects. Oxidation of exogenous glucose and glucose polymer (72 +/- 15 and 65 +/- 18%, respectively, of the 98.9 +/- 4.7 g ingested) was similar and significantly greater than exogenous fructose oxidation (54 +/- 13%). A transient rise in plasma glucose concentration was observed with glucose ingestion only. However, plasma insulin levels were similar with glucose and glucose polymer ingestions and significantly higher than with water or fructose ingestion. Plasma free fatty acid and glycerol responses to exercise were blunted with carbohydrate ingestion. However, fat utilization was not significantly different with water (82 +/- 14 g), glucose (60 +/- 3 g), fructose (59 +/- 11 g), or glucose polymer ingestion (60 +/- 8 g). Endogenous carbohydrate utilization was significantly lower with glucose (184 +/- 22 g), glucose polymer (187 +/- 31 g), and fructose (211 +/- 18 g) than with water (239 +/- 30 g) ingestion. Plasma volume slightly increased with water ingestion (7.4 +/- 4.5%), but the decrease was similar with glucose (-7.6 +/- 5.1%) and glucose polymer (-8.2 +/- 4.6%), suggesting that the rate of water delivery to plasma was similar with the two carbohydrates.(ABSTRACT TRUNCATED AT 250 WORDS)

APA, Harvard, Vancouver, ISO, and other styles

9

Parang, Keykavous. "Polymer-Supported reagents for methylphosphorylation and phosphorylation of carbohydrates." Bioorganic & Medicinal Chemistry Letters 12, no. 14 (July 2002): 1863–66. http://dx.doi.org/10.1016/s0960-894x(02)00266-4.

Full text

APA, Harvard, Vancouver, ISO, and other styles

10

Redgwell, R. J., V. Trovato, and D. Curti. "Cocoa bean carbohydrates: roasting-induced changes and polymer interactions." Food Chemistry 80, no. 4 (April 2003): 511–16. http://dx.doi.org/10.1016/s0308-8146(02)00320-5.

Full text

APA, Harvard, Vancouver, ISO, and other styles

11

Liu, Chanjuan, Chao Li, Qingfeng Niu, Chao Cai, Guoyun Li, and Guangli Yu. "Fabrication of carbohydrate microarrays on poly(2-hydroxyethyl methacrylate)-cyanuric chloride-modified substrates for the analysis of carbohydrate–lectin interactions." New Journal of Chemistry 43, no. 23 (2019): 9145–51. http://dx.doi.org/10.1039/c9nj01369e.

Full text

APA, Harvard, Vancouver, ISO, and other styles

12

Boyer, Cyrille, Jingquan Liu, Volga Bulmus, and Thomas P. Davis. "RAFT Polymer End-Group Modification and Chain Coupling/Conjugation Via Disulfide Bonds." Australian Journal of Chemistry 62, no. 8 (2009): 830. http://dx.doi.org/10.1071/ch09062.

Full text

Abstract:

End-group modification of polymers prepared by reversible addition–fragmentation chain transfer (RAFT) polymerization was accomplished by the conversion of trithiocarbonate or dithioester end-groups into a pyridyl disulfide (PDS) functionality. Several different polymers, such as poly(methyl methacrylate), polystyrene, poly(oligoethylene glycol-acrylate), poly(hydroxypropylacrylamide), and poly(N-isopropylacrylamide) were prepared by RAFT polymerization, and subjected to aminolysis in the presence of 2,2′-dithiodipyridine to yield thiol-terminated polymers with yields in the range 65–90% dependent on the polymer structure. Furthermore, this PDS end-group was utilized to generate higher-order architectures, such as diblock copolymers with high yields and selectively. In addition, the PDS end-groups were used for the bioconjugation of different biomolecules, such as oligonucleotides, carbohydrates, and peptides. The successful modification of well-defined polymers was confirmed by a combination of UV-vis, NMR spectroscopy, and gel permeation chromatography.

APA, Harvard, Vancouver, ISO, and other styles

13

Ellervik, Ulf, and Richard Johnsson. "Selective 1-O-Deacetylation of Carbohydrates Using Polymer-Bound Benzylamine." Synlett 2005, no. 19 (November 4, 2005): 2939–40. http://dx.doi.org/10.1055/s-2005-921901.

Full text

APA, Harvard, Vancouver, ISO, and other styles

14

Cuhel, Russell L., and David R. S. Lean. "Influence of Light Intensity, Light Quality, Temperature, and Daylength on Uptake and Assimilation of Carbon Dioxide and Sulfate by Lake Plankton." Canadian Journal of Fisheries and Aquatic Sciences 44, no. 12 (December 1, 1987): 2118–32. http://dx.doi.org/10.1139/f87-261.

Full text

Abstract:

The biochemical composition of newly produced phytoplankton biomass in Lake Ontario varied systematically with respect to experimentally manipulated incident light intensity and environmentally imposed water temperature and daylength, but was insensitive to light quality. Total uptake of 14C-labeled bicarbonate was light dependent (Popt:dark = 60–200), while 35SO42− uptake was light stimulated (Popt:dark < 5). Subcellular allocation of 14C for relative protein, carbohydrate, and lipid polymer synthesis responded sensitively to subsaturating light. Pathways of 35S assimilation were unaffected by light intensity. Night protein synthesis and attendant respiration of polymeric carbohydrates was a function of prior light history: with daytime illumination at Popt, day and night rates of 35SO4-S incorporation into protein were often indistinguishable. Using April–November data from Popt only, allocation of carbon to carbohydrate polymer storage for night growth was strictly proportional to nightlength. The proportion of carbon contained in protein was strongly correlated with in situ water temperature. The lack of cross-correlation suggests that temperature and daylength exert independent constraints on the biochemical composition of lake microplankton.

APA, Harvard, Vancouver, ISO, and other styles

15

Augustin, Livia S. A., Anne-Marie Aas, Arnie Astrup, Fiona S. Atkinson, Sara Baer-Sinnott, Alan W. Barclay, Jennie C. Brand-Miller, et al. "Dietary Fibre Consensus from the International Carbohydrate Quality Consortium (ICQC)." Nutrients 12, no. 9 (August 24, 2020): 2553. http://dx.doi.org/10.3390/nu12092553.

Full text

Abstract:

Dietary fibre is a generic term describing non-absorbed plant carbohydrates and small amounts of associated non-carbohydrate components. The main contributors of fibre to the diet are the cell walls of plant tissues, which are supramolecular polymer networks containing variable proportions of cellulose, hemicelluloses, pectic substances, and non-carbohydrate components, such as lignin. Other contributors of fibre are the intracellular storage oligosaccharides, such as fructans. A distinction needs to be made between intrinsic sources of dietary fibre and purified forms of fibre, given that the three-dimensional matrix of the plant cell wall confers benefits beyond fibre isolates. Movement through the digestive tract modifies the cell wall structure and may affect the interactions with the colonic microbes (e.g., small intestinally non-absorbed carbohydrates are broken down by bacteria to short-chain fatty acids, absorbed by colonocytes). These aspects, combined with the fibre associated components (e.g., micronutrients, polyphenols, phytosterols, and phytoestrogens), may contribute to the health outcomes seen with the consumption of dietary fibre. Therefore, where possible, processing should minimise the degradation of the plant cell wall structures to preserve some of its benefits. Food labelling should include dietary fibre values and distinguish between intrinsic and added fibre. Labelling may also help achieve the recommended intake of 14 g/1000 kcal/day.

APA, Harvard, Vancouver, ISO, and other styles

16

Voiland, Annie, and Georges Michel. "Structural studies of the cell wall polysaccharide of Nocardia asteroides R 399." Canadian Journal of Microbiology 31, no. 11 (November 1, 1985): 1011–18. http://dx.doi.org/10.1139/m85-191.

Full text

Abstract:

As with other bacteria belonging to the corynebacteria, mycobacteria, and nocardia group, Nocardia possess in their cell walls a neutral polysaccharide. Structural analysis of the cell wall polysaccharide of Nocardia asteroides R 399 was undertaken. The carbohydrate polymer contained D-arabinose and D-galactose as in mycobacteria. Besides these two carbohydrates we pointed out the occurrence of two additional components: D-glucose and a polyol. This polyol, because of its small amount and its uneasy detection, had been for a long time ignored. It has been proven to be the 6-deoxy-D-altritol or 1-deoxy-D-talitol. The polymer consists of a main strand composed of →5 Araf 1→ and →4Galp1→ or→5Galf1→; oligoarabinosyl side chains were localized on C3 of an arabinosyl residue. Other shorter ramifications also occur on some galactosyl units. A characterization of the linkage between polysaccharide and peptidoglycan inside the cell wall has also been carried out. The two polymers are joined by a phosphodiester bond which involves 6-deoxyaltritol. As some corynebacteria previously analyzed were also shown to contain mannose (and sometimes glucose), we can conclude that the main skeleton of cell wall polysaccharides of the corynebacteria, mycobacteria, and nocardia group of bacteria is an arabinogalactan; however, individual structural features of the polysaccharide are varying according to the bacterial species. These results might be connected with variations that were observed in immunological analysis.

APA, Harvard, Vancouver, ISO, and other styles

17

Zhao, Xin, Huijun Zhang, Jiacheng Li, Meng Tian, Juanjuan Yang, Songxuan Sun, Qixin Hu, Liu Yang, and Shiyi Zhang. "Orally administered saccharide-sequestering nanocomplex to manage carbohydrate metabolism disorders." Science Advances 7, no. 14 (March 2021): eabf7311. http://dx.doi.org/10.1126/sciadv.abf7311.

Full text

Abstract:

Excessive carbohydrate intake is linked to the growing prevalence of diabetes, nonalcoholic fatty liver disease (NAFLD), and obesity. α-Glucosidases inhibitor, the only Food and Drug Administration–approved drug for limiting the absorption of polysaccharides and disaccharides, is ineffective for monosaccharides. Here, we develop a boronic acid–containing polymer nanocomplex (Nano-Poly-BA), absorbing all saccharides into nanocomplex with the diol/boronic acid molar ratio far above 1, to prevent saccharides’ absorption in the gut. The orally administered Nano-Poly-BA is nonabsorbable and nontoxic. When tested against four kinds of carbohydrates and three real-world foods (coke, blueberry jam, and porridge), Nano-Poly-BA shows remarkable after-meal blood glucose reductions in wild-type, type 1, and type 2 diabetic mouse models. In a NAFLD mouse model induced by fructose, Nano-Poly-BA shows substantial reduction of hepatic lipogenesis. In short, the orally administered saccharide-sequestering polymer nanocomplex may help prediabetic, diabetic, overweight, and even healthy people to manage sugar intake.

APA, Harvard, Vancouver, ISO, and other styles

18

Moreno-Eutimio, Mario Adan, Nayeli Goreti Nieto-Velázquez, Lorena Espinosa-Monroy, Yessica Torres-Ramos, Araceli Montoya-Estrada, Jorge Cueto, Juan Jose Hicks, and Gustavo Acosta-Altamirano. "Potent Anti-Inflammatory Activity of Carbohydrate Polymer with Oxide of Zinc." BioMed Research International 2014 (2014): 1–8. http://dx.doi.org/10.1155/2014/712312.

Full text

Abstract:

Pebisut is a biological adhesive composed of naturally occurring carbohydrates combined with zinc oxide (ZnO) initially used as a coadjutant for healing of anastomoses. Likewise some works demonstrated that carbohydrate complexes exerts anti-inflammatory activity and it is widely known that ZnO modulate inflammation. However, the direct effects of Pebisut on isolated cells and acute inflammatory responses remained to be investigated. The present study evaluated anti-inflammatory effect of Pebisut using lipopolysaccharide (LPS) stimulated human mononuclear cells, chemotaxis, and cell infiltrationin vivoin a murine model of peritonitis. Our data show that human cells treated with different dilutions of Pebisut release less IL-6, IL-1β, and IL-8 after LPS stimuli compared with the control treated cells. In addition, Pebisut lacked chemotactic activity in human mononuclear cells but was able to reduce chemotaxis towards CCL2, CCL5, and CXCL12 that are representative mononuclear cells chemoattractants. Finally, in a murine model of peritonitis, we found less number of macrophages (F4/80+) and T lymphocytes (CD3+) in peritoneal lavages from animals treated with Pebisut. Our results suggest that Pebisut has anti-inflammatory activity, which might have a beneficial effect during anastomoses healing or wounds associated with excessive inflammation.

APA, Harvard, Vancouver, ISO, and other styles

19

Song, Wang-Ze, Yu-Bin Zheng, Jun-Hao Li, Ming Li, Kun Dong, and Karim Ullah. "Site-Selective Acylation of Carbohydrates Directed by Recyclable Polymer-Supported Isothiourea Catalysts." HETEROCYCLES 98, no. 2 (2019): 304. http://dx.doi.org/10.3987/com-18-14025.

Full text

APA, Harvard, Vancouver, ISO, and other styles

20

Barsky, E. L., G. A. Dol’nikova, Ya V. Savanina, E. E. Belousova, E. Yu Karpova, A. G. Dedov, and E. S. Lobakova. "Conversion of stillage carbohydrates by associations of microorganisms immobilized on polymer matrices." Moscow University Biological Sciences Bulletin 68, no. 3 (July 2013): 124–30. http://dx.doi.org/10.3103/s0096392513030036.

Full text

APA, Harvard, Vancouver, ISO, and other styles

21

Kamitani, Ryosuke, Kenichi Niikura, Tomohiro Onodera, Norimasa Iwasaki, Hideyuki Shimaoka, and Kuniharu Ijiro. "Patterned Immobilization of Unprotected Carbohydrates on an Aminooxy Polymer-Grafted Solid Surface." Bulletin of the Chemical Society of Japan 80, no. 9 (September 15, 2007): 1808–13. http://dx.doi.org/10.1246/bcsj.80.1808.

Full text

APA, Harvard, Vancouver, ISO, and other styles

22

Wang, Xin Cheng, Yan Lei Song, Ya Mei Wang, Chong Pin Huang, Ying Xia Li, and Biao Hua Chen. "Preparation of Lactic Acid by Polymer-Catalyzed Conversion of Maltose in Aqueous Alkaline Media." Advanced Materials Research 1004-1005 (August 2014): 947–53. http://dx.doi.org/10.4028/www.scientific.net/amr.1004-1005.947.

Full text

Abstract:

The preparation of lactic acid (LA) from the conversion of carbohydrates through chemical ways has received much attention as a way of producing platform chemicals from renewable resources, but harsh reaction conditions were usually employed especially when environmentally benign solvent (water) was used as the reaction media. In this work, polymerizates of imidazole and epichlorohydrin ([IMEP]Cl) have been used as catalysts for the conversion of maltose to LA. Several factors, including the temperature, the NaOH concentration, the [IMEP]Cl loading and the maltose concentration, were found to affect LA yield, and the process was optimized by method of orthogonal experiment. The order of significant factors was found to be maltose concentration > temperature > [IMEP]Cl loading > NaOH concentration. The optimum yield of LA was 48.5%. This route provides a new strategy for carbohydrates conversion to produce fine chemicals.

APA, Harvard, Vancouver, ISO, and other styles

23

Mierina, Inese, Reinis Vilskersts, and Māris Turks. "Delivery Systems for Birch-bark Triterpenoids and their Derivatives in Anticancer Research." Current Medicinal Chemistry 27, no. 8 (March 26, 2020): 1308–36. http://dx.doi.org/10.2174/0929867325666180530095657.

Full text

Abstract:

Birch-bark triterpenoids and their semi-synthetic derivatives possess a wide range of biological activities including cytotoxic effects on various tumor cell lines. However, due to the low solubility and bioavailability, their medicinal applications are rather limited. The use of various nanotechnology-based drug delivery systems is a rapidly developing approach to the solubilization of insufficiently bioavailable pharmaceuticals. Herein, the drug delivery systems deemed to be applicable for birch-bark triterpenoid structures are reviewed. The aforementioned disadvantages of birch-bark triterpenoids and their semi-synthetic derivatives can be overcome through their incorporation into organic nanoparticles, which include various dendrimeric systems, as well as embedding the active compounds into polymer matrices or complexation with carbohydrate nanoparticles without covalent bonding. Some of the known triterpenoid delivery systems consist of nanoparticles featuring inorganic cores covered with carbohydrates or other polymers. Methods for delivering the title compounds through encapsulation and emulsification into lipophilic media are also suitable. Besides, the birch-bark triterpenoids can form self-assembling systems with increased bio-availability. Even more, the self-assembling systems are used as carriers for delivering other chemotherapeutic agents. Another advantage besides increased bioavailability and anticancer activity is the reduced overall systemic toxicity in most of the cases, when triterpenoids are delivered with any of the carriers.

APA, Harvard, Vancouver, ISO, and other styles

24

BeMiller, James N. "Carbohydrates and carbohydrate polymers." Trends in Food Science & Technology 4, no. 9 (September 1993): 319. http://dx.doi.org/10.1016/0924-2244(93)90085-o.

Full text

APA, Harvard, Vancouver, ISO, and other styles

25

Sugii, Atsushi, Kumiko Harada, and Yasuhiro Tomita. "Separation of carbohydrates by high-performance liquid chromatography on porous pyridinium polymer columns." Journal of Chromatography A 366 (January 1986): 412–16. http://dx.doi.org/10.1016/s0021-9673(01)93493-4.

Full text

APA, Harvard, Vancouver, ISO, and other styles

26

Li, Qianjin, Tripta Kamra, and Lei Ye. "Nanoparticle-enhanced fluorescence emission for non-separation assays of carbohydrates using a boronic acid–alizarin complex." Chemical Communications 52, no. 18 (2016): 3701–4. http://dx.doi.org/10.1039/c5cc10516a.

Full text

APA, Harvard, Vancouver, ISO, and other styles

27

Davies, Donald S. "Kinetics of Icodextrin." Peritoneal Dialysis International: Journal of the International Society for Peritoneal Dialysis 14, no. 2_suppl (February 1994): 45–51. http://dx.doi.org/10.1177/089686089401402s07.

Full text

Abstract:

Icodextrin isanα-1,4 linked glucose polymer produced by hydrolysis of starch and membrane fractionation to obtain material with the desired molecular weight distribution. Icodextrin is similar in structure to physiological carbohydrates such as glycogen, but the latter has a higher degree of cross-linking through α-1,6 bonds. Icodextrin is a substrate for plasma α-amylase which hydrolyzes it to maltose, maltotriose, and maltotetrose. The fate of icodextrin administered in solution into the peritoneal cavity of patients in renal failure is determined by its stability in the peritoneal fluid, the extent of absorption, probably via the lymphatics, into the systemic circulation, and the rate of hydrolysis by plasma amylase. Early studies on a glucose polymer very similar to icodextrin demonstrated that the compounds are stable in peritoneal fluid from continuous ambulatory peritoneal dialysis (CAPD) patients, but rapidly hydrolyzed by plasma. Absorption of polymer from the peritoneal cavity was approximately 28% during a 12-hour dwell. In these studies it was apparent that hydrolysis products of up to four glucose units readily passed from the blood to the dialysis fluid, but higher molecular weight fragments wereexcluded. In the MIDAS study in which patients were treated with a single daily exchange of 2 L of 7.5% icodextrin, plasma samples were obtained during visit 2 (pretreatment with icodextrin), visit 6 (1 month after commencement of treatment), visit 9 (3 months), and visit 12 (6 months) and analyzed for icodextrin and metabolites. Steady-state plasma levels of icodextrin of approximately 4.6 mg/mL and maltose of 1.1 mg/mL were stable at 1,3, and 6 months. During special studies, when the dwell time for icodextrin and the comparator glucose solutions were controlled to 8 or 12 hours, dialysate was analyzed for polymer and metabolites. Total carbohydrate lost from the dialysate was approximately 19.6% after 8 hours and 33.5% after 12 hours. This compares with a mean of 85.6% of absorbed carbohydrate in 7 patients treated with strong glucose (6 on 3.86%, 1 on 2.27% glucose) for 8 hours. Plasma levels of icodextrin and maltose were measured in 12 patients who stopped once-a-day treatment with the polymer after approximately 2 years. Icodextrin (4.8 mg/mL) and maltose (1.1 mg/mL) fell to pretreatment levels in 7 10 days. On recommencement of treatment with polymer, plasma levels rose to steady-state levels of 4.7 mg/mL for icodextrin and 1.1 mg/mL for maltose in 7 -10 days. Icodextrin in solution in the peritoneal cavity is absorbed into the blood stream, probably via the lymphatic system. The extent of absorption depends on the dwell time of the solution; about 20% of total carbohydrate is absorbed in 8 hours, and this rises to 34% at 12 hours. There is no evidence of metabolism of glucose polymers like icodextrin in the peritoneal cavity. Icodextrin in the systemic circulation is hydrolyzed, probably by plasma and tissue α-amylase, to oligosaccharides, such as maltose, maltotriose and maltotetrose. These may be further metabolized, eliminated by peritoneal dialysis, or, if the patient has residual renal function, excreted in urine. The rapid attainment of steady-state plasma levels of icodextrin and its metabolites and the rapid decline when treatment is stopped is strong evidence against extensive tissue storage of the polymer.

APA, Harvard, Vancouver, ISO, and other styles

28

Pereira, Mark P., Michael A. D'Elia, Justyna Troczynska, and Eric D. Brown. "Duplication of Teichoic Acid Biosynthetic Genes in Staphylococcus aureus Leads to Functionally Redundant Poly(Ribitol Phosphate) Polymerases." Journal of Bacteriology 190, no. 16 (June 13, 2008): 5642–49. http://dx.doi.org/10.1128/jb.00526-08.

Full text

Abstract:

ABSTRACT Wall teichoic acids are anionic phosphate-rich polymers that are part of the complex meshwork of carbohydrates that make up the gram-positive cell wall. These polymers are essential to the proper rod-shaped morphology of Bacillus subtilis and have been shown to be an important virulence determinant in the nosocomial opportunistic pathogen Staphylococcus aureus. Together, sequence-based studies, in vitro experiments with biosynthetic proteins, and analyses of the chemical structure of wall teichoic acid have begun to shed considerable light on our understanding of the biogenesis of this polymer. Nevertheless, some paradoxes remain unresolved. One of these involves a putative duplication of genes linked to CDP-ribitol synthesis (tarI′J′ and tarIJ) as well as poly(ribitol phosphate) polymerization (tarK and tarL) in S. aureus. In the work reported here, we performed careful studies of the dispensability of each gene and discovered a functional redundancy in the duplicated gene clusters. We were able to create mutants in either of the putative ribitol phosphate polymerases (encoded by tarK and tarL) without affecting teichoic acid levels in the S. aureus cell wall. Although genes linked to CDP-ribitol synthesis are also duplicated, a null mutant in only one of these (tarI′J′) could be obtained, while tarIJ remained essential. Suppression analysis of the tarIJ null mutant indicated that the mechanism of dysfunction in tarI′J′ is due to poor translation of the TarJ′ enzyme, which catalyzes the rate-limiting step in CDP-ribitol formation. This work provides new insights into understanding the complex synthetic steps of the ribitol phosphate polymer in S. aureus and has implications on specifically targeting enzymes involved in polymer biosynthesis for antimicrobial design.

APA, Harvard, Vancouver, ISO, and other styles

29

Temesgen, Selamu, Mirko Rennert, Tamrat Tesfaye, and Michael Nase. "Review on Spinning of Biopolymer Fibers from Starch." Polymers 13, no. 7 (April 1, 2021): 1121. http://dx.doi.org/10.3390/polym13071121.

Full text

Abstract:

Increasing interest in bio-based polymers and fibers has led to the development of several alternatives to conventional plastics and fibers made of these materials. Biopolymer fibers can be made from renewable, environmentally friendly resources and can be fully biodegradable. Biogenic resources with a high content of carbohydrates such as starch-containing plants have huge potentials to substitute conventional synthetic plastics in a number of applications. Much literature is available on the production and modification of starch-based fibers and blends of starch with other polymers. Chemistry and structure–property relationships of starch show that it can be used as an attractive source of raw material which can be exploited for conversion into a number of high-value bio-based products. In this review, possible spinning techniques for the development of virgin starch or starch/polymer blend fibers and their products are discussed. Beneficiation of starch for the development of bio-based fibers can result in the sustainable replacement of oil-based high-value materials with cost-effective, environmentally friendly, and abundant products.

APA, Harvard, Vancouver, ISO, and other styles

30

Zhou, Huacong, Jinliang Song, Xinchen Kang, Jiayin Hu, Yingying Yang, Honglei Fan, Qinglei Meng, and Buxing Han. "One-pot conversion of carbohydrates into gamma-valerolactone catalyzed by highly cross-linked ionic liquid polymer and Co/TiO2." RSC Advances 5, no. 20 (2015): 15267–73. http://dx.doi.org/10.1039/c4ra14363a.

Full text

APA, Harvard, Vancouver, ISO, and other styles

31

Pedersen, Nanna Bjerregaard, Notburga Gierlinger, and Lisbeth Garbrecht Thygesen. "Bacterial and abiotic decay in waterlogged archaeological Picea abies (L.) Karst studied by confocal Raman imaging and ATR-FTIR spectroscopy." Holzforschung 69, no. 1 (January 1, 2015): 103–12. http://dx.doi.org/10.1515/hf-2014-0024.

Full text

Abstract:

Abstract Waterlogged archaeological Norway spruce [Picea abies (L.) Karst] poles were studied by means of confocal Raman imaging (CRI) and attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) analysis to determine lignin and polysaccharide composition and distribution in the cell wall. The waterlogged archaeological wood (WAW) was submerged under anoxic conditions for approximately 400 years and solely decayed by erosion bacteria (EB). CRI showed that decayed tracheids contain a residual material (RM) with heterogeneous lignin distribution; within the same tracheid RM often contained regions with intensities lower than sound S2 layers up to intensity values as high as the compound middle lamella (CML). CRI revealed strong depletion of carbohydrates in RM which indicated that EB are able to utilise the carbohydrate fraction of the cell wall effectively. Raman bands assigned to lignin did not show any difference between RM and sound S2. This is a hint that EB do not modify the lignin structure. Sound WAW free from EB decay showed evidence of loss of acetyl groups in glucomannan, loss of un-conjugated ester linkages in the lignin-carbohydrate complexes between xylan and lignin, and minor oxidation of the lignin polymer compared to recent reference material. This is evidence for abiotic decay in the course of waterlogging.

APA, Harvard, Vancouver, ISO, and other styles

32

Deden, Mohammad, Abdul Rahim, and Asrawaty Asrawaty. "SIFAT FISIK DAN KIMIA EDIBLE FILM PATI UMBI GADUNG PADA BERBAGAI KONSENTRASI." Jurnal Pengolahan Pangan 5, no. 1 (June 30, 2020): 26–33. http://dx.doi.org/10.31970/pangan.v5i1.35.

Full text

Abstract:

Today, the use of synthetic polymers as plastics has an important role in the economy of modern industrial society. Plastic packaging is often used as a food packaging material. However, the use of plastics can pollute the environment, because plastic is difficult to degrade naturally. One alternative to replacing the use of conventional plastics as food packaging is biodegradable plastic called edible film. The use of gadung tuber starch as a raw material for making edible films will not disturb food stability, because gadung is not consumed such as rice, corn and cassava. Gadung tubers are very good for edible film polymer materials containing high carbohydrates. Aim to determine the physical and chemical properties of the edible film starch of gadung tubers at various concentrations. The conclusion is that the optimum conditions for making edible films are good at 6% starch concentration with KA 11.50% and an average thickness of 0.13 mm.

APA, Harvard, Vancouver, ISO, and other styles

33

Nieminen, Kaarlo, Lidia Testova, Markus Paananen, and Herbert Sixta. "Novel insight in carbohydrate degradation during alkaline treatment." Holzforschung 69, no. 6 (August 1, 2015): 667–75. http://dx.doi.org/10.1515/hf-2014-0306.

Full text

Abstract:

Abstract A mathematical model is presented, in which the yield loss (YL) and the decline in polymerization of carbohydrates is comprehended. The model is applicable to the treatment of cellulose and hemicelluloses in alkaline media, and it features the actions of peeling, stopping, and alkaline hydrolysis of the polymer chains. The peeling reaction is further subdivided into primary and secondary peeling depending on whether it originates from an initial reducing end-group (REG) or from an REG created by alkaline hydrolysis. Fitting the model to experimental data provides estimates of the various reaction rate constants. When available, simultaneous observations of the YL and the decrease in chain length contribute to the evaluation of the parameters. Alternatively, if the data are limited to the YL, the obtained parameter estimates allow for a projection of the time development of chain length. The model has been applied on data from two types of experiments: soda-anthraquinone treatment of cotton linters and kraft treatment of Scots pine. It was possible to evaluate the impact of the different processes on degradation as well as the portions of polymer chains possessing active or stabilized REGs.

APA, Harvard, Vancouver, ISO, and other styles

34

Будагаева (Budagaeva), Валентина (Valentina) Григорьевна (Grigor'evna), Арюна (Ariuna) Арсалановна (Arsalanovna) Раднагуруева (Radnagurueva), Елена (Elena) Владимировна (Vladimirovna) Лаврентьева (Lavrent'eva), Дарима (Darima) Дондоковна (Dondokovna) Бархутова (Barkhutova), and Даниил (Daniil) Николаевич (Nikolaevich) Оленников (Olennikov). "CARBOHYDRATES OF MICROBIAL MATHS OF ALKALINE HYDROTHERMS OF BAIKAL REGION." chemistry of plant raw material, no. 1 (October 17, 2017): 45–51. http://dx.doi.org/10.14258/jcprm.2018012168.

Full text

Abstract:

Alkaline hydrotherms of the Baikal region are extreme aquatic ecosystems characterized by the presence of the specific microbial communities, mats. A study of the carbohydrate composition of the biomass of microbial maths from four hydrothermal waters of the Baikal region (Alla, Garga, Seya, Umkhei) showed the presence of mannitol (1,93–7,25 mg/g, from the dry weight), uronic acids (1,15–15,85 mg/g) and neutral monosaccharides. The latter were galactose (2,02–56,56 mg/g), glucose (2,00–45,96 mg/g), mannose (4,83–78,86 mg/g), xylose (1,18–10,53 mg/g), fucose (0,23–2,40 mg/g), and arabinose and rhamnose as a trace. It is shown that the mats from the studied hydrothermal waters of the Baikal region characterized by the different ratio of carbohydrate groups and a specific monosaccharide composition. A fraction of water-soluble polysaccharides was isolated from the biomass of the microbial mat of Seya hydrotherm. It was a mixture of seven components with molecular masses from 122 to 1700 kDa. The dominant polymer Se-WSPS-07 with a molecular weight 122 kDa was isolated and preliminarily characterized as a heteropolysaccharide containing galactose, glucose, mannose as dominant monosaccharides, and protein (5,92%). It was found that Se-WSPS-07 possesses biological activity demonstrating its perspectiveness for the further study as a therapeutic agent. The chemical characteristics of the carbohydrate components of microbial maths from the alkaline hydrotherms of the Baikal region were realized for the first time.

APA, Harvard, Vancouver, ISO, and other styles

35

Zhang, Zhang, Bin Du, Li-Jia Zhang, Yu-Xia Da, Zheng-Jun Quan, Liang-Jie Yang, and Xi-Cun Wang. "Conversion of carbohydrates into 5-hydroxymethylfurfural using polymer bound sulfonic acids as efficient and recyclable catalysts." RSC Advances 3, no. 24 (2013): 9201. http://dx.doi.org/10.1039/c3ra41912f.

Full text

APA, Harvard, Vancouver, ISO, and other styles

36

Dong, Kaijun, Jun Zhang, Weimin Luo, Lin Su, and Zhilin Huang. "Catalytic conversion of carbohydrates into 5-hydroxymethyl furfural over sulfonated hyper-cross-linked polymer in DMSO." Chemical Engineering Journal 334 (February 2018): 1055–64. http://dx.doi.org/10.1016/j.cej.2017.10.092.

Full text

APA, Harvard, Vancouver, ISO, and other styles

37

Gu, Jing, Jun Zhang, Denian Li, Haoran Yuan, and Yong Chen. "Hyper‐cross‐linked polymer based carbonaceous materials as efficient catalysts for ethyl levulinate production from carbohydrates." Journal of Chemical Technology & Biotechnology 94, no. 10 (July 17, 2019): 3073–83. http://dx.doi.org/10.1002/jctb.6107.

Full text

APA, Harvard, Vancouver, ISO, and other styles

38

Cordes, David B., and Bakthan Singaram. "A unique, two-component sensing system for fluorescence detection of glucose and other carbohydrates." Pure and Applied Chemistry 84, no. 11 (May 2, 2012): 2183–202. http://dx.doi.org/10.1351/pac-con-11-10-36.

Full text

Abstract:

In our glucose-sensing system, a boronic acid-modified viologen molecule quenches the fluorescence of a separate dye molecule. When glucose or other monosaccharides are added and bind to the boronic acid, the quenching ability of the viologen is diminished and fluorescence increases. Thus, changes in the fluorescence of the dye can be correlated with changing glucose concentration. Quenching and sugar-sensing results are explained by an electrostatic interaction between dye and quencher. This modular system can be configured in a nearly unlimited number of ways through substitution and multiplexing of the two fundamental quencher and dye components. Significantly, fluorescent quantum dots (QDs) can also be used as the reporter component. The system can also be immobilized in a hydrogel polymer to provide real-time, reversible sugar sensing.

APA, Harvard, Vancouver, ISO, and other styles

39

Osono, Takashi. "Decomposition of Organic Chemical Components in Wood by Tropical Xylaria Species." Journal of Fungi 6, no. 4 (September 23, 2020): 186. http://dx.doi.org/10.3390/jof6040186.

Full text

Abstract:

The ability of Xylaria species obtained from tropical wood and leaf litter to cause a mass loss of lignin and carbohydrates in wood was examined in vitro with pure culture decomposition tests. The mass loss of wood of four tree species caused by nine Xylaria isolates ranged from 4.5% to 28.4% of the original wood mass. These Xylaria isolates have a potential ability to decompose lignin and other recalcitrant compounds, collectively registered as acid unhydrolyzable residues or Klason lignin in wood. The origin of isolates (i.e., isolates from wood versus leaf litter) did not affect the mass loss of acid unhydrolyzable residue in wood. The Xylaria isolates tested generally caused a selective decomposition of polymer carbohydrates in wood in preference to acid unhydrolyzable residue. The mass loss of acid unhydrolyzable residue caused by Xylaria isolates varied with the tree species of the wood and was negatively related to the initial content of acid unhydrolyzable residue in wood, implying the limiting effect of lignin and recalcitrant compounds on wood decomposition by Xylaria isolates.

APA, Harvard, Vancouver, ISO, and other styles

40

Wagenmakers, A. J., F. Brouns, W. H. Saris, and D. Halliday. "Oxidation rates of orally ingested carbohydrates during prolonged exercise in men." Journal of Applied Physiology 75, no. 6 (December 1, 1993): 2774–80. http://dx.doi.org/10.1152/jappl.1993.75.6.2774.

Full text

Abstract:

Six male volunteers exercised on a cycle ergometer at 65% of maximal work load for 120 min on six occasions while ingesting water (W) only, four doses of maltodextrin (M) [0.92, 1.85, 2.77, and 3.70 g/kg body wt (4, 8, 12, and 16% M, respectively)], and sucrose (S) [1.85 g/kg body wt (8% S)]. Drinks were given during warm-up (8 ml/kg body wt) and each 15 min during exercise (2 ml/kg body wt). M and S were of high 13C natural abundance. Total carbohydrate (CHO) and fat oxidations were calculated from the nonprotein respiratory exchange ratio. M and S increased total CHO oxidation compared with W; no difference was observed between CHO solutions. Total CHO oxidation decreased continuously with time and more rapidly after W than after M or S. Fat oxidation increased continuously in all treatments. Oxidation rates of ingested CHO were 52 +/- 19, 76 +/- 12, 86 +/- 10, and 91 +/- 9 g/2 h for 4, 8, 12, and 16% M, respectively. The oxidation rate of S was 81 +/- 10 g/2 h (not different from 8% M), which indicated that the glucose polymer had no advantage over S. Oxidation rates of M and S increased to a plateau after 90–120 min of exercise. For all solutions except 4% M, the plateau oxidation rate was close to 1.0 g/min. Differences between 8, 12, and 16% M and 8% S were minimal such that ingestion of 8% M or S may well have had an optimal ergogenic effect.(ABSTRACT TRUNCATED AT 250 WORDS)

APA, Harvard, Vancouver, ISO, and other styles

41

Ahmadibeni, Yousef, and Keykavous Parang. "Polymer-Bound Oxathiaphospholane: A Solid-Phase Reagent for Regioselective Monothiophosphorylation and Monophosphorylation of Unprotected Nucleosides and Carbohydrates." Organic Letters 7, no. 10 (May 2005): 1955–58. http://dx.doi.org/10.1021/ol050385w.

Full text

APA, Harvard, Vancouver, ISO, and other styles

42

Zhang, Jun, Kaijun Dong, Weimin Luo, and Haifeng Guan. "Catalytic upgrading of carbohydrates into 5-ethoxymethylfurfural using SO3H functionalized hyper-cross-linked polymer based carbonaceous materials." Fuel 234 (December 2018): 664–73. http://dx.doi.org/10.1016/j.fuel.2018.07.060.

Full text

APA, Harvard, Vancouver, ISO, and other styles

43

Zhang, Luxin, Yujie Zhu, Lu Tian, Yunfei He, Hao Wang, and Fuyuan Deng. "One-pot alcoholysis of carbohydrates to biofuel 5-ethoxymethylfufural and 5-methoxymethylfufural via a sulfonic porous polymer." Fuel Processing Technology 193 (October 2019): 39–47. http://dx.doi.org/10.1016/j.fuproc.2019.05.001.

Full text

APA, Harvard, Vancouver, ISO, and other styles

44

Pinzner, Florian, Thorsten Keller, Jürgen Mut, Julian Bechold, Jürgen Seibel, and Jürgen Groll. "Polyoxazolines with a Vicinally Double-Bioactivated Terminus for Biomacromolecular Affinity Assessment." Sensors 21, no. 9 (May 1, 2021): 3153. http://dx.doi.org/10.3390/s21093153.

Full text

Abstract:

Interactions between proteins and carbohydrates with larger biomacromolecules, e.g., lectins, are usually examined using self-assembled monolayers on target gold surfaces as a simplified model measuring setup. However, most of those measuring setups are either limited to a single substrate or do not allow for control over ligand distance and spacing. Here, we develop a synthetic strategy, consisting of a cascade of a thioesterification, native chemical ligation (NCL) and thiol-ene reaction, in order to create three-component polymer conjugates with a defined double bioactivation at the chain end. The target architecture is the vicinal attachment of two biomolecule residues to the α telechelic end point of a polymer and a thioether group at the ω chain end for fixating the conjugate to a gold sensor chip surface. As proof-of-principle studies for affinity measurements, we demonstrate the interaction between covalently bound mannose and ConA in surface acoustic wave (SAW) and surface plasmon resonance (SPR) experiments.

APA, Harvard, Vancouver, ISO, and other styles

45

Larsen, M. H., J. J. Leisner, and H. Ingmer. "The Chitinolytic Activity of Listeria monocytogenes EGD Is Regulated by Carbohydrates but Also by the Virulence Regulator PrfA." Applied and Environmental Microbiology 76, no. 19 (July 30, 2010): 6470–76. http://dx.doi.org/10.1128/aem.00297-10.

Full text

Abstract:

ABSTRACT Chitin, an insoluble polymer of N-acetyl-d-glucosamine (GlcNAc), is one of the most abundant carbohydrate polymers in marine and terrestrial environments. Chitin hydrolysis by Listeria monocytogenes depends on two chitinase-encoding genes, chiA and chiB, and the aim of this study was to investigate their regulation. Chitin induces the expression of both chitinases in late exponential growth phase, and chiA but not chiB is furthermore induced by the monomer GlcNAc. Furthermore, their expression is subjected to catabolite control. Chitinases expressed by bacterial pathogens have proven to be important not only for nutrient acquisition and environmental survival but also for infecting animals and humans. Interestingly, the central L. monocytogenes virulence gene regulator, PrfA, is required for the chitinolytic phenotype, as chitinase activity was significantly reduced in prfA mutant cells compared to its level in wild-type cells. In agreement with this, Northern blot analysis showed that the amounts of chiA and chiB transcripts upon induction by chitin were significantly lower in the prfA mutant than in the wild type. The chitinolytic activity and chiA and chiB expression were reduced in the absence of the sigB gene, indicating that σB is also important for the production of chitinases. The chiA, chiB, and chiA chiB mutants were not impaired for in vitro adhesion and invasion in epithelial cell lines, but the chiA chiB double mutant showed less survival ability in a chitin-enriched medium. The regulation of chitinolytic activity in L. monocytogenes is complex, and taken together, the results indicate that the biological role of this activity may not be limited to the external environment.

APA, Harvard, Vancouver, ISO, and other styles

46

Dhevaraj, J., S. Vembu, S. Pazhamalai, and M. Gopalakrishnan. "“Design and Synthesis of Some Cyclic Carbohydrates with Norfloxacin as Surface moiety. A Study of Sustained Relax of Drugs”." Oriental Journal of Chemistry 35, no. 2 (April 16, 2019): 577–90. http://dx.doi.org/10.13005/ojc/350211.

Full text

Abstract:

Biocompatible and biodegradable sustained drug delivery system has been constructed from reaction between norfloxacin and cyclodextrin through secondary amine of piperazine ring and hydroxyl group of the carbohydrate. Covalent bond polymeric structure is designed by the help of chloroacetyl chloride, target dendrimer formed by removing two hydrochloride molecules. The development of cyclodextrin core drug delivery system with twenty one norfloxacin surface moiety has been synthesized by only two steps. The synthesized polymeric structure was thoroughly studied by NMR, FT-IR, MALDI and UV- spectrometry. Sustained release assessment of synthetic polymer studied through different buffer solution by UV spectrometry and norfloxacin releases rate of synthetic polymer was controlled by the concentration and the experimental medium. The microbial assessments through kinetic studies by using Escherichia coli also reveal that the norfloxacin released possesses potential antimicrobial activity. Antibacterial activity of synthesized drug delivery system has been investigated with gram-negative and gram-positive species like Escherichia coli (mtcc 443), bacillus subtilis (mtcc 2063), pseudomonas (mtcc 741), staphylococcus (mtcc 737) and proteus mirabilis (mtcc 425). The hydrophobic and hydrophilic balance and the repeat drug unit of this synthesized system are responsible for effective antibacterial activity. The minimum inhibitor concentration values of this system are very small to 100 µg/mL-1, synthesized compound shown five times improved activity against organism on comparism with standard drug. The in-vitro release of norfloxacin from obtained dendrimer was investigated.

APA, Harvard, Vancouver, ISO, and other styles

47

Wood, Ian P., Enriqueta Garcia-Gutierrez, Nikolaus Wellner, and Keith W. Waldron. "Feedstock selection for polymer and chemical production: feedstock-specific recalcitrance." Faraday Discussions 202 (2017): 391–402. http://dx.doi.org/10.1039/c7fd00044h.

Full text

Abstract:

Plant cell wall materials derived from a range of waste biomass sources have great potential as a source of sustainable alternatives to petrochemicals. Perhaps the most straightforward way of realising this potential would be to hydrolyse the most efficiently fermentable polymers into their constituent sugars and use yeast to ferment these into useful chemicals. However, it also makes sense to pre-extract components which have a greater value in polymeric form. This is particularly true for non-cellulosic polymers, which are rich in poorly-fermentable pentose sugars. Liquid hot water (LHW) pretreatment can be used to extract non-cellulosic carbohydrates in a cost-effective manner, leaving a cellulose-rich substrate which is easier to hydrolyse using commercial cellulases. However, inherent differences in the plant cell wall structure and composition mean that some biomass sources may be more suitable for exploitation than others. Here, we examine eight different feedstocks (two each from hardwood, softwood, cereal straws and dicotyledonous crops), expose them to 26 different LHW pretreatment conditions and hydrolyse the entire pretreated slurry with a commercial cellulase. This enables side-by-side comparisons, in terms of saccharification yield, of the feedstocks. The results clearly demonstrate considerable differences in suitability between the feedstocks, in relation to the quantity of products released and the processes needed to obtain them.

APA, Harvard, Vancouver, ISO, and other styles

48

Fang, Yan, Ting He, Hao Gao, Lingling Fan, Jingyuan Liu, Binrui Li, Haowei Zhang, and Huiyu Bai. "Polymer Membrane with Glycosylated Surface by a Chemo-Enzymatic Strategy for Protein Affinity Adsorption." Catalysts 10, no. 4 (April 9, 2020): 415. http://dx.doi.org/10.3390/catal10040415.

Full text

Abstract:

Membranes with glycosylated surfaces are naturally biomimetic and not only have excellent surface hydrophilicity and biocompatibility, but have a specific recognition to target biomacromolecules due to the unique chemo-biological properties of their surface carbohydrates; however, they cannot be easily chemically produced on large scales due to the complex preparation process. This manuscript describes the fabrication of a polypropylene membrane with a glycosylated surface by a chemo-enzymatic strategy. First, hydroxyl (OH) groups were introduced onto the surface of microporous polypropylene membrane (MPPM) by UV-induced grafting polymerization of oligo(ethylene glycol) methacrylate (OEGMA). Then, glycosylation of the OH groups with galactose moieties was achieved via an enzymatic transglycosylation by β-galactosidase (Gal) recombinanted from E. coli. The fabricated glycosylated membrane showed surprisingly specific affinity adsorption to lectin ricinus communis agglutinin (RCA120). The chemo-enzymatic route is easy and green, and it would be expected to have wide applications for large-scale preparation of polymer membranes with glycosylated surfaces.

APA, Harvard, Vancouver, ISO, and other styles

49

Mitomo, Shun-ichi, Yukiko Negishi, Toshiki Mutai, and Yutaka Inoue. "Development of a Novel Surface Porous Polymer Core-shell Ion-Exchange Filler and its Elution Behavior with Carbohydrates." Journal of Life Support Engineering 31, no. 4 (December 31, 2019): 158–62. http://dx.doi.org/10.5136/lifesupport.31.158.

Full text

APA, Harvard, Vancouver, ISO, and other styles

50

Álvarez-Chávez, Jimena, Mar Villamiel, Liliana Santos-Zea, and Aurea K. Ramírez-Jiménez. "Agave By-Products: An Overview of Their Nutraceutical Value, Current Applications, and Processing Methods." Polysaccharides 2, no. 3 (September 21, 2021): 720–43. http://dx.doi.org/10.3390/polysaccharides2030044.

Full text

Abstract:

Agave, commonly known as “maguey” is an important part of the Mexican tradition and economy, and is mainly used for the production of alcoholic beverages, such as tequila. Industrial exploitation generates by-products, including leaves, bagasse, and fibers, that can be re-valorized. Agave is composed of cellulose, hemicellulose, lignin, fructans, and pectin, as well as simple carbohydrates. Regarding functional properties, fructans content makes agave a potential source of prebiotics with the capability to lower blood glucose and enhance lipid homeostasis when it is incorporated as a prebiotic ingredient in cookies and granola bars. Agave also has phytochemicals, such as saponins and flavonoids, conferring anti-inflammatory, antioxidant, antimicrobial, and anticancer properties, among other benefits. Agave fibers are used for polymer-based composite reinforcement and elaboration, due to their thermo-mechanical properties. Agave bagasse is considered a promising biofuel feedstock, attributed to its high-water efficiency and biomass productivity, as well as its high carbohydrate content. The optimization of physical and chemical pretreatments, enzymatic saccharification and fermentation are key for biofuel production. Emerging technologies, such as ultrasound, can provide an alternative to current pretreatment processes. In conclusion, agaves are a rich source of by-products with a wide range of potential industrial applications, therefore novel processing methods are being explored for a sustainable re-valorization of these residues.

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Carbohydrates polymer'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles