Home About us Contact
|
Home About us Contact | ||
|
|
||
Shorter Chain Length (shorter + chain_length)
Selected AbstractsFREE RADICAL-SCAVENGING ACTIVITIES OF LOW MOLECULAR WEIGHT CHITIN OLIGOSACCHARIDES LEAD TO ANTIOXIDANT EFFECT IN LIVE CELLSJOURNAL OF FOOD BIOCHEMISTRY, Issue 2010DAI-NGHIEP NGO ABSTRACT Chitin oligosaccharides (NA-COS) with low molecular weight distribution of 229.21,593.12 Da were produced from crab chitin by acid hydrolysis. They showed reducing power and scavenging effect on 1,1-diphenyl-2-picrylhydrazyl (DPPH) (Sigma Chemical Co., St. Louis, MO), hydroxyl and alkyl radicals. It was observed that the radical-scavenging activity of NA-COS increased in a dose-dependent manner. Their IC50 values for DPPH, hydroxyl and alkyl radicals were 0.8, 1.75 and 1.14 mg/mL, respectively. Furthermore, NA-COS exhibited the inhibitory effect on the oxidative damage of DNA from human lymphoma U937 (American Type Culture Collection, Manassas, VA) and the direct radical-scavenging effect in human fibrosarcoma cells (HT1080) (American Type Culture Collection) in 2,,7,-dichlorofluorescin diacetate (DCFH-DA) assay (Molecular Probes Inc., Eugene, OR). The results suggest that NA-COS can exert antioxidant effect in live cells and have the potential to be applied to food supplements or nutraceuticals. PRACTICAL APPLICATIONS Chitin oligosaccharides (NA-COS) are the hydrolyzed products of chitin (KEUMHO chemical products Co. Ltd., Gyeongbuk, Korea) of which derivatives have shown antioxidant, antimicrobial, anticancer, anti-inflammatory and immunostimulant effects. According to previous studies, NA-COS have beneficial biological activities similar to those of chitin. Furthermore, they are easily soluble in water because of their shorter chain length. Therefore, NA-COS are potentially applicable to improve food quality and human health. [source] Effects of alcoholic solvents on the conductivity of tosylate-doped poly(3,4-ethylenedioxythiophene) (PEDOT-OTs)POLYMER INTERNATIONAL, Issue 1 2006Tae Young Kim Abstract The effects of alcoholic solvents on the charge transport properties of tosylate-doped poly(3,4-ethylenedioxythiophene) (PEDOT-OTs) are investigated. The use of different alcoholic solvents in the oxidative chemical polymerization of 3,4-ethylenedioxythiophene (EDOT) with iron(III)- p -tosylate led to a change in the electrical conductivity of PEDOT-OTs. For example, PEDOT-OTs prepared from methanol shows a conductivity of 20.1 S cm,1 which is enhanced by a factor of 200 as compared to PEDOT-OTs prepared from hexanol. The variation of charge transport properties on the use of different alcoholic solvents is consistent with the data recorded by UV-visible and electrospin resonance (ESR) measurements. From XPS experiments, the PEDOT-OTs samples prepared from different alcoholic solvents were found to have almost the same doping level, suggesting that the number of charge carriers is not responsible for the change in conductivity. Supported by XRD results, it was found that the use of alcoholic solvents with shorter chain length induces more efficient packing of PEDOT chains. It is proposed that the alcoholic solvents associated with the counter ion of PEDOT via hydrogen bonding give rise to a change in the molecular ordering of PEDOT chains during the polymerization step, hence enhancing or depressing the inter-chain hopping rate of the resulting PEDOT-OTs. Copyright © 2005 Society of Chemical Industry [source] The change in characteristics of microcrystalline cellulose during wet granulation using a high-shear mixerJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 5 2001Tatsuya Suzuki The objective of this study was to investigate the mechanism of hard granule formation and to demonstrate the applicability of X-ray diffraction methods for studying the polymeric pharmaceutical excipients. Using a high-shear mixer, microcrystalline cellulose (MCC) was granulated with water as the granulating liquid. The hardness of the MCC granules increased with granulation time and the amount of water added. The specific surface area measured by the N2 adsorption method was reduced during the process. Crystallite size of cellulose, calculated by Scherrer's equation adapted for wide angle X-ray diffraction method, decreased with granulation time and with increasing amounts of water added. Debye plots for X-ray small scattering patterns suggested that the average magnitude of the continuous solid region in MCC granules became significantly greater, whereas the specific surface area of the MCC granules, calculated from Debye plots, became smaller in comparison with that of intact MCC. These findings suggested that the long-chain structures in MCC were disrupted, resulting in smaller units with shorter chain lengths due to the strong shear force of the impeller. These smaller units then form a network within the granules. Thus, MCC granules are strengthened with longer granulation time and greater amounts of water, resulting in a more intricate network. The change in MCC chain length and physical structure can be experimentally detected using the small-angle X-ray scattering and wide-angle powder X-ray diffraction methods. [source] In situ localisation and quantification of surfactins in a Bacillus subtilis swarming community by imaging mass spectrometryPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 18 2008Delphine Debois Abstract Surfactins are a family of heptacyclopeptides in which the C-terminal carbonyl is linked with the ,-hydroxy group of a fatty acid acylating the N-terminal function of a glutamic acid residue. The fatty acyl chain is 12,16 carbon atoms long. These compounds, which are secreted by the Gram-positive bacterium Bacillus subtilis in stationary phase in liquid cultures, play an important role in swarming communities on the surface of agar media in the formation of dendritic patterns. TOF secondary ion MS (TOF-SIMS) imaging was used to map surfactins within 16,17,h swarming patterns, with a 2,,m spatial resolution. Surfactins were mainly located in the central mother colony (the site of initial inoculation), in a ,ring' surrounding the pattern and along the edges of the dendrites. In the mother colony and the interior of the dendrites, surfactins with shorter chain lengths are present, whereas in the ring surrounding the swarm community and between dendrites, surfactins with longer fatty acyl chain lengths were found. A quantitative analysis by MALDI-TOF MS showed a concentration gradient of surfactin from the mother colony to the periphery. The concentration of surfactin was ,400,pmol/mL in the mother colony and ,10,pmol/mL at the base of the dendrites, decreasing to 2,pmol/mL at their tips. [source] | ||||||||||