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Sample records for chitosan improves maize

  1. Seed priming with chitosan improves maize germination and seedling growth in relation to physiological changes under low temperature stress

    Institute of Scientific and Technical Information of China (English)

    Ya-jing GUAN; Jin HU; Xian-ju WANG; Chen-xia SHAO

    2009-01-01

    Low temperature stress during germination and early seedling growth is an important constraint of global production of maize. The effects of seed priming with 0.25%, 0.50%, and 0.75% (w/v) chitosan solutions at 15 ℃ on the growth and physiological changes were investigated using two maize (Zea mays L.) inbred lines, HuangC (chilling-tolerant) and Mo17 (chilling-sensitive). While seed priming with chitosan had no significant effect on germination percentage under low temperature stress, it enhanced germination index, reduced the mean germination time (MGT), and increased shoot height, root length, and shoot and root dry weights in both maize lines. The decline of malondialdehyde (MDA) content and relative permeability of the plasma membrane and the increase of the concentrations of soluble sugars and proline, peroxidase (POD) activity, and catalase (CAT) activity were detected both in the chilling-sensitive and chilling-tolerant maize seedlings after priming with the three concentrations of chitosan. HuangC was less sensitive to responding to different concentrations of chitosan. Priming with 0.50% chitosan for about 60~64 h seemed to have the best effects. Thus, it suggests that seed priming with chitosan may improve the speed of germination of maize seed and benefit for seedling growth under low temperature stress.

  2. Seed priming with chitosan improves maize germination and seedling growth in relation to physiological changes under low temperature stress*

    OpenAIRE

    Guan, Ya-jing; Hu, Jin; Wang, Xian-Ju; Shao, Chen-xia

    2009-01-01

    Low temperature stress during germination and early seedling growth is an important constraint of global production of maize. The effects of seed priming with 0.25%, 0.50%, and 0.75% (w/v) chitosan solutions at 15 °C on the growth and physiological changes were investigated using two maize (Zea mays L.) inbred lines, HuangC (chilling-tolerant) and Mo17 (chilling-sensitive). While seed priming with chitosan had no significant effect on germination percentage under low temperature stress, it en...

  3. Synergistic Effects of Plant Growth Promoting Rhizobacteria and Chitosan on In Vitro Seeds Germination, Greenhouse Growth, and Nutrient Uptake of Maize (Zea mays L.).

    Science.gov (United States)

    Agbodjato, Nadège A; Noumavo, Pacôme A; Adjanohoun, Adolphe; Agbessi, Léonce; Baba-Moussa, Lamine

    2016-01-01

    This study aimed to assess the effects of three plant growth promoting rhizobacteria (PGPR) and chitosan either singly or in combination on maize seeds germination and growth and nutrient uptake. Maize seeds were treated with chitosan and bacterial solution. The germination and growth tests were carried out in square Petri dishes and plastic pots. The combination chitosan-A. lipoferum-P. fluorescens has increased the seeds vigor index up to 36.44% compared to the control. In comparison to the control, P. putida has significantly improved root weight (44.84%) and germinated seed weight (31.39%) whereas chitosan-P. putida has increased the shoot weight (65.67%). For the growth test, the maximal heights (17.66%) were obtained by plants treated with the combination A. lipoferum-P. fluorescens-P. putida. Chitosan-P. fluorescens induced the highest increases of leaves per plant (50.09%), aerial (84.66%), and underground biomass (108.77%) production. The plants inoculated with A. lipoferum had the large leaf areas with an increase of 54.08%, while combinations P. fluorescens-P. putida and chitosan-A. lipoferum improved the aerial and underground dry matter of plants to 26.35% and 18.18%. The nitrogen content of the plants was increased by chitosan-A. lipoferum-P. fluorescens-P. putida with an increasing of 41.61%. The combination of chitosan and PGPR can be used as biological fertilizers to increase maize production. PMID:26904295

  4. Synergistic Effects of Plant Growth Promoting Rhizobacteria and Chitosan on In Vitro Seeds Germination, Greenhouse Growth, and Nutrient Uptake of Maize (Zea mays L.

    Directory of Open Access Journals (Sweden)

    Nadège A. Agbodjato

    2016-01-01

    Full Text Available This study aimed to assess the effects of three plant growth promoting rhizobacteria (PGPR and chitosan either singly or in combination on maize seeds germination and growth and nutrient uptake. Maize seeds were treated with chitosan and bacterial solution. The germination and growth tests were carried out in square Petri dishes and plastic pots. The combination chitosan-A. lipoferum-P. fluorescens has increased the seeds vigor index up to 36.44% compared to the control. In comparison to the control, P. putida has significantly improved root weight (44.84% and germinated seed weight (31.39% whereas chitosan-P. putida has increased the shoot weight (65.67%. For the growth test, the maximal heights (17.66% were obtained by plants treated with the combination A. lipoferum-P. fluorescens-P. putida. Chitosan-P. fluorescens induced the highest increases of leaves per plant (50.09%, aerial (84.66%, and underground biomass (108.77% production. The plants inoculated with A. lipoferum had the large leaf areas with an increase of 54.08%, while combinations P. fluorescens-P. putida and chitosan-A. lipoferum improved the aerial and underground dry matter of plants to 26.35% and 18.18%. The nitrogen content of the plants was increased by chitosan-A. lipoferum-P. fluorescens-P. putida with an increasing of 41.61%. The combination of chitosan and PGPR can be used as biological fertilizers to increase maize production.

  5. ADVANCES IN TRANSGENIC MAIZE FOR QUALITY IMPROVEMENT

    Directory of Open Access Journals (Sweden)

    M.Rajendar Reddy

    2015-12-01

    Full Text Available Maize (Zea mays is a major food and animal feed worldwide and occupies a relevant place in the world economy and trade as an industrial grain crop. Currently more than 70% of maize production is used for food and feed; therefore, knowledge of genes involved in grain structure and chemical is important for improving the nutritional and food-making properties of maize. It is a good source of carbohydrates, fats, proteins, vitamins and minerals but deficient in two essential amino acids, Viz., lysine and tryptophan. To overcome this problem and to improve the above quality characters the maize breeders have followed different strategies like opaque 2, QPM and development of transgenic maize with improved quality characters. Finally we can conclude that the conventional breeding techniques and now plant biotechnology are helping meet the growing demand for food production, nutrition security while preserving our environment for future generations

  6. Synergistic Effects of Plant Growth Promoting Rhizobacteria and Chitosan on In Vitro Seeds Germination, Greenhouse Growth, and Nutrient Uptake of Maize (Zea mays L.)

    OpenAIRE

    Agbodjato, Nadège A.; Pacôme A. Noumavo; Adolphe Adjanohoun; Léonce Agbessi; Lamine Baba-Moussa

    2016-01-01

    This study aimed to assess the effects of three plant growth promoting rhizobacteria (PGPR) and chitosan either singly or in combination on maize seeds germination and growth and nutrient uptake. Maize seeds were treated with chitosan and bacterial solution. The germination and growth tests were carried out in square Petri dishes and plastic pots. The combination chitosan-A. lipoferum-P. fluorescens has increased the seeds vigor index up to 36.44% compared to the control. In comparison to the...

  7. Cu-Chitosan Nanoparticle Mediated Sustainable Approach To Enhance Seedling Growth in Maize by Mobilizing Reserved Food.

    Science.gov (United States)

    Saharan, Vinod; Kumaraswamy, R V; Choudhary, Ram Chandra; Kumari, Sarita; Pal, Ajay; Raliya, Ramesh; Biswas, Pratim

    2016-08-10

    Food crop seedlings often have susceptibility to various abiotic and biotic stresses. Therefore, in the present study, we investigated the impact of Cu-chitosan nanoparticles (NPs) on physiological and biochemical changes during maize seedling growth. Higher values of percent germination, shoot and root length, root number, seedling length, fresh and dry weight, and seed vigor index were obtained at 0.04-0.12% concentrations of Cu-chitosan NPs as compared to water, CuSO4, and bulk chitosan treatments. Cu-chitosan NPs at the same concentrations induced the activities of α-amylase and protease enzymes and also increased the total protein content in germinating seeds. The increased activities of α-amylase and protease enzymes corroborated with decreased content of starch and protein, respectively, in the germinating seeds. Cu-chitosan NPs at 0.16% and CuSO4 at 0.01% concentrations showed inhibitory effect on seedling growth. The observed results on seedling growth could be explained by the toxicity of excess Cu and growth promotory effect of Cu-chitosan NPs. Physiological and biochemical studies suggest that Cu-chitosan NPs enhance the seedling growth of maize by mobilizing the reserved food, primarily starch, through the higher activity of α-amylase. PMID:27460439

  8. Maize seed coatings and seedling sprayings with chitosan and hydrogen peroxide: their influence on some phenological and biochemical behaviors

    OpenAIRE

    Lizárraga-Paulín, Eva-Guadalupe; Miranda-Castro, Susana-Patricia; Moreno-Martínez, Ernesto; Lara-Sagahón, Alma-Virginia; Torres-Pacheco, Irineo

    2013-01-01

    Objective: To evaluate the effect of chitosan (CH) and hydrogen peroxide (H2O2) seed coatings and seedling sprinklings on two different maize varieties by measuring their phenology, the H2O2 presence, the catalase (CAT) activity, and the protein quantity. Methods: Seven groups of ten seeds for each maize variety were treated with CH (2% (20 g/L) and 0.2% (2 g/L)) or H2O2 (8 mmol/L) by coating, sprinkling, or both. Germination and seedling growth were measured. One month after germination, the...

  9. Comparative population genomics of maize domestication and improvement.

    Science.gov (United States)

    Hufford, Matthew B; Xu, Xun; van Heerwaarden, Joost; Pyhäjärvi, Tanja; Chia, Jer-Ming; Cartwright, Reed A; Elshire, Robert J; Glaubitz, Jeffrey C; Guill, Kate E; Kaeppler, Shawn M; Lai, Jinsheng; Morrell, Peter L; Shannon, Laura M; Song, Chi; Springer, Nathan M; Swanson-Wagner, Ruth A; Tiffin, Peter; Wang, Jun; Zhang, Gengyun; Doebley, John; McMullen, Michael D; Ware, Doreen; Buckler, Edward S; Yang, Shuang; Ross-Ibarra, Jeffrey

    2012-06-03

    Domestication and plant breeding are ongoing 10,000-year-old evolutionary experiments that have radically altered wild species to meet human needs. Maize has undergone a particularly striking transformation. Researchers have sought for decades to identify the genes underlying maize evolution, but these efforts have been limited in scope. Here, we report a comprehensive assessment of the evolution of modern maize based on the genome-wide resequencing of 75 wild, landrace and improved maize lines. We find evidence of recovery of diversity after domestication, likely introgression from wild relatives, and evidence for stronger selection during domestication than improvement. We identify a number of genes with stronger signals of selection than those previously shown to underlie major morphological changes. Finally, through transcriptome-wide analysis of gene expression, we find evidence both consistent with removal of cis-acting variation during maize domestication and improvement and suggestive of modern breeding having increased dominance in expression while targeting highly expressed genes.

  10. Maize seed coatings and seedling sprayings with chitosan and hydrogen peroxide: their influence on some phenological and biochemical behaviors

    Science.gov (United States)

    Lizárraga-Paulín, Eva-Guadalupe; Miranda-Castro, Susana-Patricia; Moreno-Martínez, Ernesto; Lara-Sagahón, Alma-Virginia; Torres-Pacheco, Irineo

    2013-01-01

    Objective: To evaluate the effect of chitosan (CH) and hydrogen peroxide (H2O2) seed coatings and seedling sprinklings on two different maize varieties by measuring their phenology, the H2O2 presence, the catalase (CAT) activity, and the protein quantity. Methods: Seven groups of ten seeds for each maize variety were treated with CH (2% (20 g/L) and 0.2% (2 g/L)) or H2O2 (8 mmol/L) by coating, sprinkling, or both. Germination and seedling growth were measured. One month after germination, the presence of H2O2 in seedlings in the coated seed treatments was evaluated. Protein content and CAT activity were determined under all treatments. Results: H2O2 seed coating enhanced the germination rate and increased seedling and stem length in the quality protein maize (QPM) variety. Seedlings had a higher emergence velocity under this treatment in both varieties. CH and H2O2 sprinklings did not have an effect on seedling phenology. Exogenous application of H2O2 promoted an increase of endogenous H2O2. CH and H2O2 seedling sprinkling increased the protein content in both maize varieties, while there was no significant effect on the CAT activity of treated seeds and seedlings. Conclusions: CH and H2O2 enhance some phenological and biochemical features of maize depending on their method of application. PMID:23365007

  11. Silicon Improves Maize Photosynthesis in Saline-Alkaline Soils

    Directory of Open Access Journals (Sweden)

    Zhiming Xie

    2015-01-01

    Full Text Available The research aimed to determine the effects of Si application on photosynthetic characteristics of maize on saline-alkaline soil, including photosynthetic rate (Pn, stomatal conductance (gs, transpiration rate (E, and intercellular CO2 concentration (Ci of maize in the field with five levels (0, 45, 90, 150, and 225 kg·ha−1 of Si supplying. Experimental results showed that the values of Pn, gs, and Ci of maize were significantly enhanced while the values of E of maize were dramatically decreased by certain doses of silicon fertilizers, which meant that Si application with proper doses significantly increased photosynthetic efficiency of maize in different growth stages under stressing environment of saline-alkaline soil. The optimal dose of Si application in this experiment was 150 kg·ha−1 Si. It indicated that increase in maize photosynthesis under saline-alkaline stress took place by Si application with proper doses, which is helpful to improve growth and yield of maize.

  12. Adoption of Improved Maize Seed Varieties in Southern Zambia

    OpenAIRE

    Thomson Kalinda; Gelson Tembo; Elias Kuntashula

    2014-01-01

    Maize is the principal agricultural crop produced by Zambian smallholder farmers for household consumption and sale. Their production strategy is therefore important in meeting food security and income needs. This study uses data collected from a survey of a random sample of farm households in southern Zambia to develop a Tobit regression model. The model identifies farm and farmer characteristics important for adoption of improved maize seed varieties as well as to determine the role of farm...

  13. Maize seed coatings and seedling sprayings with chitosan and hydrogen peroxide:their influence on some phenological and biochemical behaviors

    Institute of Scientific and Technical Information of China (English)

    Eva-Guadalupe LIZ(A)RRAGA-PAUL(I)N; Susana-Patricia MIRANDA-CASTRO; Ernesto MORENO-MART(I)NEZ; Alma-Virginia LARA-SAGAH(O)N; Irineo TORRES-PACHECO

    2013-01-01

    Objective:To evaluate the effect of chitosan(CH)and hydrogen peroxide(H2O2)seed coatings and seedling sprinklings on two different maize varieties by measuring their phenology,the H2O2 presence,the catalase (CAT)activity,and the protein quantity.Methods:Seven groups of ten seeds for each maize variety were treated with CH(2%(20 g/L)and 0.2%(2 g/L))or H2O2(8 mmol/L)by coating,sprinkling,or both.Germination and seedling growth were measured.One month after germination,the presence of H2O2 in seedlings in the coated seed treatments was evaluated.Protein content and CAT activity were determined under all treatments.Results:H2O2 seed coating enhanced the germination rate and increased seedling and stem length in the quality protein maize(QPM)variety.Seedlings had a higher emergence velocity under this treatment in both varieties.CH and H2O2 sprinklings did not have an effect on seedling phenology.Exogenous application of H2O2 promoted an increase of endogenous H2O2.CH and H2O2 seedling sprinkling increased the protein content in both maize varieties,while there was no significant effect on the CAT activity of treated seeds and seedlings.Conclusions:CH and H2O2 enhance some phenological and biochemical features of maize depending on their method of application.

  14. Combined effect of chitosan and water activity on growth and fumonisin production by Fusarium verticillioides and Fusarium proliferatum on maize-based media.

    Science.gov (United States)

    Ferrochio, Laura V; Cendoya, Eugenia; Zachetti, Vanessa G L; Farnochi, Maria C; Massad, Walter; Ramirez, Maria L

    2014-08-18

    The objectives of the present study were to determine the in vitro efficacy of chitosan (0.5, 1.0, 2.0 and 3.0mg/mL) under different water availabilities (0.995, 0.99, 0.98, 0.96 and 0.93) at 25°C on lag phase, growth rate and fumonisin production by isolates of Fusarium verticillioides and Fusarium proliferatum. The presence of chitosan affected growth and fumonisin production, and this effect was dependent on the dose and aW treatment used. The presence of chitosan increased the lag phase, and reduced the growth rate of both Fusarium species significantly at all concentrations used, especially at 0.93 aW. Also, significant reduction of fumonisin production was observed in both Fusarium species at all conditions assayed. The present study has shown the combined effects of chitosan and aW on growth and fumonisin production by the two most important Fusarium species present on maize. Low molecular weight (Mw) chitosan with more than 70% of degree of deacetylation (DD) at 0.5mg/mL was able to significantly reduce growth rate and fumonisin production on maize-based media, with maximum levels of reduction in both parameters obtained at the highest doses used. As fumonisins are unavoidable contaminants in food and feed chains, their presence needs to be reduced to minimize their effects on human and animal health and to diminish the annual market loss through rejected maize. In this scenario post-harvest use of chitosan could be an important alternative treatment.

  15. Improving effects of chitosan nanofiber scaffolds on osteoblast proliferation and maturation.

    Science.gov (United States)

    Ho, Ming-Hua; Liao, Mei-Hsiu; Lin, Yi-Ling; Lai, Chien-Hao; Lin, Pei-I; Chen, Ruei-Ming

    2014-01-01

    Osteoblast maturation plays a key role in regulating osteogenesis. Electrospun nanofibrous products were reported to possess a high surface area and porosity. In this study, we developed chitosan nanofibers and examined the effects of nanofibrous scaffolds on osteoblast maturation and the possible mechanisms. Macro- and micro observations of the chitosan nanofibers revealed that these nanoproducts had a flat surface and well-distributed fibers with nanoscale diameters. Mouse osteoblasts were able to attach onto the chitosan nanofiber scaffolds, and the scaffolds degraded in a time-dependent manner. Analysis by scanning electron microscopy further showed mouse osteoblasts adhered onto the scaffolds along the nanofibers, and cell-cell communication was also detected. Mouse osteoblasts grew much better on chitosan nanofiber scaffolds than on chitosan films. In addition, human osteoblasts were able to adhere and grow on the chitosan nanofiber scaffolds. Interestingly, culturing human osteoblasts on chitosan nanofiber scaffolds time-dependently increased DNA replication and cell proliferation. In parallel, administration of human osteoblasts onto chitosan nanofibers significantly induced osteopontin, osteocalcin, and alkaline phosphatase (ALP) messenger (m)RNA expression. As to the mechanism, chitosan nanofibers triggered runt-related transcription factor 2 mRNA and protein syntheses. Consequently, results of ALP-, alizarin red-, and von Kossa-staining analyses showed that chitosan nanofibers improved osteoblast mineralization. Taken together, results of this study demonstrate that chitosan nanofibers can stimulate osteoblast proliferation and maturation via runt-related transcription factor 2-mediated regulation of osteoblast-associated osteopontin, osteocalcin, and ALP gene expression. PMID:25246786

  16. Nanoparticle-mediated interplay of chitosan and melatonin for improved wound epithelialisation.

    Science.gov (United States)

    Blažević, Filip; Milekić, Tamara; Romić, Marieta Duvnjak; Juretić, Marina; Pepić, Ivan; Filipović-Grčić, Jelena; Lovrić, Jasmina; Hafner, Anita

    2016-08-01

    Herein, we propose an innovative approach to improving wound healing. Our strategy is to deliver melatonin locally at the wound site by means of lecithin/chitosan nanoparticles. We used four types of chitosan that differed in terms of molecular weight and/or deacetylation degree. Melatonin encapsulation efficiency, nanoparticle size, zeta potential, biocompatibility and in vitro drug release were studied as a function of the type of chitosan used in preparation. The nanoparticles were evaluated in terms of their potential to promote wound epithelialisation via an in vitro scratch assay using a human keratinocyte (HaCaT) monolayer. The model wounds were treated with nanoparticle suspensions at a chitosan concentration of 5μgml(-1), which was based on preceding cell biocompatibility studies. Nanoparticles prepared with different types of chitosan showed similar effect on the keratinocyte proliferation/migration. Nanoparticle-mediated interplay of chitosan and melatonin was shown to be crucial for improved wound epithelialisation. PMID:27112895

  17. Impact of Improved Maize Adoption on Welfare of Farm Households in Malawi: A Panel Data Analysis

    OpenAIRE

    Bezu, Sosina; Kassie, Girma; Shiferaw, Bekele; Ricker-Gilbert, Jacob

    2013-01-01

    This paper assesses improved maize adoption in Malawi and examines the link between adoption and household welfare using a three-year household panel data. The distributional effect of maize technology adoption is also investigated by looking at impacts across wealth and gender groups. We applied control function approach and IV regression to control for endogeneity of input subsidy and improved maize adoption. We found that modern maize variety adoption is positively correlated with the hous...

  18. Chitosan fibers with improved biological and mechanical properties for tissue engineering applications.

    Science.gov (United States)

    Albanna, Mohammad Z; Bou-Akl, Therese H; Blowytsky, Oksana; Walters, Henry L; Matthew, Howard W T

    2013-04-01

    The low mechanical properties of hydrogel materials such as chitosan hinder their broad utility for tissue engineering applications. Previous research efforts improved the mechanical properties of chitosan fiber through chemical and physical modifications; however, unfavorable toxicity effects on cells were reported. In this paper, we report the preparation of chitosan fibers with improved mechanical and biocompatibility properties. The structure-property relationships of extruded chitosan fibers were explored by varying acetic acid (AA) concentration, ammonia concentration, annealing temperature and degree of heparin crosslinking. Results showed that optimizing AA concentration to 2vol% improved fiber strength and stiffness by 2-fold. Extruding chitosan solution into 25wt% of ammonia solution reduced fiber diameters and improved fiber strength by 2-fold and stiffness by 3-fold, due to an increase in crystallinity as confirmed by XRD. Fiber annealing further reduced fiber diameter and improved fiber strength and stiffness as temperature increased. Chitosan fibers crosslinked with heparin had increased diameter but lower strength and stiffness properties and higher breaking strain values. When individual parameters were combined, further improvement in fiber mechanical properties was achieved. All mechanically improved fibers and heparin crosslinked fibers promoted valvular interstitial cells (VIC) attachment and growth over 10 day cultures. Our results demonstrate the ability to substantially improve the mechanical properties of chitosan fibers without adversely affecting their biological properties. The investigated treatments offer numerous advantages over previous physical/chemical modifications and thus are expected to expand the utility of chitosan fibers with tunable mechanical properties in various tissue engineering applications.

  19. Econometric analysis of improved maize varieties and sustainable agricultural practices (SAPs) in Eastern Zambia

    NARCIS (Netherlands)

    Manda, J.

    2016-01-01

    Maize is the principle food staple in Zambia, providing both food and income for most of the rural populace. It is estimated that over 50% of the daily caloric intake is derived from maize; with an average consumption of over 85kg per year. Because of the importance of maize, a number of improved ma

  20. Adoption of Improved Maize Seed Varieties in Southern Zambia

    Directory of Open Access Journals (Sweden)

    Thomson Kalinda

    2014-01-01

    Full Text Available Maize is the principal agricultural crop produced by Zambian smallholder farmers for household consumption and sale. Their production strategy is therefore important in meeting food security and income needs. This study uses data collected from a survey of a random sample of farm households in southern Zambia to develop a Tobit regression model. The model identifies farm and farmer characteristics important for adoption of improved maize seed varieties as well as to determine the role of farmer perceptions of technology attributes in maize varietal adoption. The results indicate that expectations about output price and yield are important determinants of adoption. Other factors directly correlated with the probability of adoption include the status of being male-headed, farm size and membership to farmer organizations. Households with more wealth and educated heads were also significantly more likely to adopt improved varieties. Some of the policy implications of these findings are that intervention strategies should be designed and implemented to encourage poor households and those with low levels of formal education to participate in local farmer organizations. The positive interaction between membership to organizations and the adoption of technologies also suggests that group based extension approaches should be encouraged not only for their role in collective action but also for their positive impact on information diffusion and technology adoption.

  1. Improved mechanical properties of chitosan fibers with applications to degradable radar countermeasure chaff

    Science.gov (United States)

    Knaul, Jonathan Zvi

    The objective of this work has been to improve the mechanical properties of wet spun chitosan fibers for applications to a degradable form of radar countermeasure chaff. The first part of the study characterizes the chitosan used for spinning. Three methods for determining the degree of deacetylation (% DDA) were used and they include titration, elemental analysis, and first derivative ultraviolet (UV) spectrometry. The molecular weight of the chitosan was determined in a solvent system of 0.25 M CH3COOH/0.25 M CH3COONa, using viscometry and gel permeation chromatography (GPC). Several samples of chitosan were used with the % DDA varying from 64.3 to 96.0%. The Mark-Houwink-Sakurada constants used for the determination of viscosity average molecular weight and the universal calibration of the HPLC system were K = 1.40 x 10 -4 dL/g and a = 0.83, respectively. A literature review of molecular weight analysis of chitosan is included. Preliminary wet spinning experiments involved a coagulation rate study which demonstrated that 1 M KOH was an effective coagulant for wet spinning and that the rate of coagulation increases with decreasing solvent ratio in the spin dope. A drying study confirmed the effectiveness of a methanol drying bath followed by a heated roller at 50°C. Following these studies, a wet spinning system was constructed and used. A lack of published data exists concerning the subjects of chitosan fiber spinning and mechanical improvements to both wet and dry chitosan fibers. Several post-spinning modification experiments focused on the reaction of the dried as-spun chitosan fibers with aqueous agents including potassium dihydrogen phosphate (KH2PO4), potassium hydrogen phthalate (KHP), glutaraldehyde (GA), and glyoxal (GLY). For the aqueous buffering agents of KH2PO4, and KHP, the highest mechanical properties resulted from solutions containing phthalate ions at pH 5.00, and from solutions containing phosphate ions at pH 5.39. The best time and

  2. Silica Modified Chitosan/Polyethylenimine Nanogel for Improved Stability and Gene Carrier Ability.

    Science.gov (United States)

    Tian, Rui; Xian, Lei; Li, Yuan; Zheng, Xingwang

    2016-05-01

    Although chitosan-based hydrogel has been widely used as a gene carrier material, further improvement in this aspect is still needed. Herein a new method was proposed for preparing the effective chitosan-based gene carrier nanogel. The new method based on the fact that supra-molecular interactions between silica, polyethylenimine (PEI) and chitosan could be used to self-assemble them together to form a rigid and stable gene carrier material in the reverse microemulsion system. When compared with chemical cross-linking route, the proposed method is simple and easy to adjust components of the resulting nanogel and, therefore, can improve its gene carrying ability. Our results showed that, doping of the PEI and silica into the chitosan hydrogel obviously increased its strength, stability and gene carrying ability. PMID:27483943

  3. Hydrophobic surface modification of chitosan gels by stearyl for improving the activity of immobilized lipase

    Institute of Scientific and Technical Information of China (English)

    Hong Tao Deng; Juan Juan Wang; Miao Ma; Zhong Yang Liu; Fei Zheng

    2009-01-01

    The hydrophobic surface modification of chitosan gels was carded out using the amidating reaction of amido groups on a gel surface with steafic acid activated by 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride (EDC) and N-hydroxy-succinimide (NHS). Lipases from Candida rugosa were adsorbed on the nascent chitosan gels (CS) and stearyl-modified gels (SCS) with different degrees of amidation. The increased surface hydrophobicity of chitosan gels improved the adsorption capacity and activity of the immobilized lipase. SCS with 31.46% amidation showed the maximum activity retention (83.43%). The experimental results suggest that the moderate surface hydrophilicity/hydropbobicity of chitosan gels is necessary for the improvement of the activity of immobilized lipase.

  4. Injectable porous nano-hydroxyapatite/chitosan/tripolyphosphate scaffolds with improved compressive strength for bone regeneration.

    Science.gov (United States)

    Uswatta, Suren P; Okeke, Israel U; Jayasuriya, Ambalangodage C

    2016-12-01

    In this study we have fabricated porous injectable spherical scaffolds using chitosan biopolymer, sodium tripolyphosphate (TPP) and nano-hydroxyapatite (nHA). TPP was primarily used as an ionic crosslinker to crosslink nHA/chitosan droplets. We hypothesized that incorporating nHA into chitosan could support osteoconduction by emulating the mineralized cortical bone structure, and improve the Ultimate Compressive Strength (UCS) of the scaffolds. We prepared chitosan solutions with 0.5%, 1% and 2% (w/v) nHA concentration and used simple coacervation and lyophilization techniques to obtain spherical scaffolds. Lyophilized spherical scaffolds had a mean diameter of 1.33mm (n=25). Further, portion from each group lyophilized scaffolds were soaked and dried to obtain Lyophilized Soaked and Dried (LSD) scaffolds. LSD scaffolds had a mean diameter of 0.93mm (n=25) which is promising property for the injectability. Scanning Electron Microscopy images showed porous surface morphology and interconnected pore structures inside the scaffolds. Lyophilized and LSD scaffolds had surface pores chitosan LSD scaffolds exhibited UCS of 8.59MPa compared to UCS of 2% nHA/chitosan lyophilized scaffolds at 3.93MPa. Standardize UCS values were 79.98MPa and 357MPa for 2% nHA/chitosan lyophilized and LSD particles respectively. One-way ANOVA results showed a significant increase (pchitosan lyophilized scaffolds compared to 0% and 0.5% nHA/chitosan lyophilized scaffolds. Moreover, 2% nHA LSD scaffolds had significantly increased (pchitosan scaffolds showed higher osteoblast attachment than 0% nHA/chitosan scaffolds. PMID:27612741

  5. Improving effects of chitosan nanofiber scaffolds on osteoblast proliferation and maturation

    Directory of Open Access Journals (Sweden)

    Ho MH

    2014-09-01

    showed that chitosan nanofibers improved osteoblast mineralization. Taken together, results of this study demonstrate that chitosan nanofibers can stimulate osteoblast proliferation and maturation via runt-related transcription factor 2-mediated regulation of osteoblast-associated osteopontin, osteocalcin, and ALP gene expression. Keywords: chitosan nanofibers, osteoblast-associated gene expression, osteoblast maturation, Runx2

  6. Improvement of HDL- and LDL-cholesterol levels in diabetic subjects by feeding bread containing chitosan.

    Science.gov (United States)

    Ausar, S F; Morcillo, M; León, A E; Ribotta, P D; Masih, R; Vilaro Mainero, M; Amigone, J L; Rubin, G; Lescano, C; Castagna, L F; Beltramo, D M; Diaz, G; Bianco, I D

    2003-01-01

    In this work we evaluated the efficacy and safety of a bread formulation containing chitosan in dyslipidemic type 2 diabetic subjects. For this purpose a total of 18 patients were allowed to incorporate to their habitual diets 120 g/day of bread containing 2% (wt/wt) chitosan (chitosan group, n= 9) or standard bread (control group, n= 9). Before the study and after 12 weeks on the modified diet, the following parameters were evaluated: body weight, plasma cholesterol, high-density lipoprotein (HDL)-cholesterol, low-density lipoprotein (LDL)-cholesterol, triglyceride, and hemoglobin A(1c) (HbA(1c)). Compared with the control group, the patients receiving chitosan-containing bread decreased their mean levels of LDL-cholesterol and significantly increased their mean levels of HDL-cholesterol at the end of the study. There were no significant differences in the body weight, serum triglyceride, and HbA(1c). These results suggest that chitosan incorporated into bread formulations could improve the lipoprotein balance similar to typical biliary salts trappers, increasing the HDL- and lowering the LDL-cholesterol, without changing the triglyceride levels. These results warrant further studies over a longer period of time to evaluate if a persistent improvement in levels of lipoproteins can be attained with this strategy.

  7. Input subsidies to improve smallholder maize productivity in Malawi: toward an african green revolution.

    OpenAIRE

    Glenn Denning; Patrick Kabambe; Pedro Sanchez; Alia Malik; Rafael Flor; Rebbie Harawa; Phelire Nkhoma; Colleen Zamba; Clement Banda; Chrispin Magombo; Michael Keating; Justine Wangila; Jeffrey Sachs

    2009-01-01

    Recent hikes in food prices have created economic and social turmoil in many African countries. But in Malawi, fertilizer and seed subsidies have enabled small-scale farmers to improve maize productivity and achieve food security.

  8. Chitosan-based leather functional coatings with improved antimicrobial properties

    OpenAIRE

    Amaral, J.S.; Fernandes, I.P.; De Pinto, V; Ferreira, M. J.; Barreiro, M.F.

    2012-01-01

    Among the interesting biological activities that have been ascribed to chitosan, the antimicrobial activity is probably the one that generates the higher number of applications. Developing antimicrobial coatings for footwear components to be used in direct contact with the feet is of great interest; both at industrial level (reducing the possibility of material deterioration and quality loss) and from the consumer’s point of view (decreasing skin infections and minimizing...

  9. Chitosan improves anti-biofilm efficacy of gentamicin through facilitating antibiotic penetration.

    Science.gov (United States)

    Mu, Haibo; Guo, Fan; Niu, Hong; Liu, Qianjin; Wang, Shunchun; Duan, Jinyou

    2014-12-03

    Antibiotic overuse is one of the major drivers in the generation of antibiotic resistant "super bugs" that can potentially cause serious effects on health. In this study, we reported that the polycationic polysaccharide, chitosan could improve the efficacy of a given antibiotic (gentamicin) to combat bacterial biofilms, the universal lifestyle of microbes in the world. Short- or long-term treatment with the mixture of chitosan and gentamicin resulted in the dispersal of Listeria monocytogenes (L. monocytogenes) biofilms. In this combination, chitosan with a moderate molecular mass (~13 kDa) and high N-deacetylation degree (~88% DD) elicited an optimal anti-biofilm and bactericidal activity. Mechanistic insights indicated that chitosan facilitated the entry of gentamicin into the architecture of L. monocytogenes biofilms. Finally, we showed that this combination was also effective in the eradication of biofilms built by two other Listeria species, Listeria welshimeri and Listeria innocua. Thus, our findings pointed out that chitosan supplementation might overcome the resistance of Listeria biofilms to gentamicin, which might be helpful in prevention of gentamicin overuse in case of combating Listeria biofilms when this specific antibiotic was recommended.

  10. Chitosan Improves Anti-Biofilm Efficacy of Gentamicin through Facilitating Antibiotic Penetration

    Directory of Open Access Journals (Sweden)

    Haibo Mu

    2014-12-01

    Full Text Available Antibiotic overuse is one of the major drivers in the generation of antibiotic resistant “super bugs” that can potentially cause serious effects on health. In this study, we reported that the polycationic polysaccharide, chitosan could improve the efficacy of a given antibiotic (gentamicin to combat bacterial biofilms, the universal lifestyle of microbes in the world. Short- or long-term treatment with the mixture of chitosan and gentamicin resulted in the dispersal of Listeria monocytogenes (L. monocytogenes biofilms. In this combination, chitosan with a moderate molecular mass (~13 kDa and high N-deacetylation degree (~88% DD elicited an optimal anti-biofilm and bactericidal activity. Mechanistic insights indicated that chitosan facilitated the entry of gentamicin into the architecture of L. monocytogenes biofilms. Finally, we showed that this combination was also effective in the eradication of biofilms built by two other Listeria species, Listeria welshimeri and Listeria innocua. Thus, our findings pointed out that chitosan supplementation might overcome the resistance of Listeria biofilms to gentamicin, which might be helpful in prevention of gentamicin overuse in case of combating Listeria biofilms when this specific antibiotic was recommended.

  11. Collagen tissue treated with chitosan solutions in carbonic acid for improved biological prosthetic heart valves.

    Science.gov (United States)

    Gallyamov, Marat O; Chaschin, Ivan S; Khokhlova, Marina A; Grigorev, Timofey E; Bakuleva, Natalia P; Lyutova, Irina G; Kondratenko, Janna E; Badun, Gennadii A; Chernysheva, Maria G; Khokhlov, Alexei R

    2014-04-01

    Calcification of bovine pericardium dramatically shortens typical lifetimes of biological prosthetic heart valves and thus precludes their choice for younger patients. The aim of the present work is to demonstrate that the calcification is to be mitigated by means of treatment of bovine pericardium in solutions of chitosan in carbonic acid, i.e. water saturated with carbon dioxide at high pressure. This acidic aqueous fluid unusually combines antimicrobial properties with absolute biocompatibility as far as at normal pressure it decomposes spontaneously and completely into H2O and CO2. Yet, at high pressures it can protonate and dissolve chitosan materials with different degrees of acetylation (in the range of 16-33%, at least) without any further pretreatment. Even exposure of the bovine pericardium in pure carbonic acid solution without chitosan already favours certain reduction in calcification, somewhat improved mechanical properties, complete biocompatibility and evident antimicrobial activity of the treated collagen tissue. The reason may be due to high extraction ability of this peculiar compressed fluidic mixture. Moreover, exposure of the bovine pericardium in solutions of chitosan in carbonic acid introduces even better mechanical properties and highly pronounced antimicrobial activity of the modified collagen tissue against adherence and biofilm formation of relevant Gram-positive and Gram-negative strains. Yet, the most important achievement is the detected dramatic reduction in calcification for such modified collagen tissues in spite of the fact that the amount of the thus introduced chitosan is rather small (typically ca. 1wt.%), which has been reliably detected using original tritium labelling method. We believe that these improved properties are achieved due to particularly deep and uniform impregnation of the collagen matrix with chitosan from its pressurised solutions in carbonic acid. PMID:24582232

  12. Label-free immunosensor based on one-step electrodeposition of chitosan-gold nanoparticles biocompatible film on Au microelectrode for determination of aflatoxin B1 in maize.

    Science.gov (United States)

    Ma, Haihua; Sun, Jizhou; Zhang, Yuan; Bian, Chao; Xia, Shanhong; Zhen, Tong

    2016-06-15

    Gold nanoparticles (AuNPs) embedded in chitosan (CHI) film, well-dispersed and smaller in size (about 10 nm), were fabricated by one-step electrodeposion on Au microelectrode in solution containing chitosan and chloride trihydrate. The nano-structure CHI-AuNPs composite film offers abundant amine groups, good conductivity, excellent biocompatibility and stability for antibody immobilization. The combination of aflatoxin B1 (AFB1) with immobilized antibody introduces a barrier to electron transfer, resulting in current decreasement. The morphologies and characterizations of modified microelectrodes were investigated by scanning electron microscope (SEM), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and Fourier transform infrared spectroscopy (FT-IR). The proposed non-enzyme and label-free immunosensor exhibited high sensitive amperometric response to AFB1 concentration in two linear ranges of 0.1 to 1 ng mL(-1) and 1 to 30 ng mL(-1), with the detection limit of 0.06 ng mL(-1) (S/N=3). The immunoassay was also applied for analysis of maize samples spiked with AFB1. Considering the sample extraction procedure, the linear range and limit of detection were assessed to be 1.6-16 ng mL(-1) and 0.19 ng mL(-1) respectively. The simple method showed good fabrication controllability and reproducibility for immunosensor design. PMID:26851579

  13. Collagen tissue treated with chitosan solutions in carbonic acid for improved biological prosthetic heart valves

    Energy Technology Data Exchange (ETDEWEB)

    Gallyamov, Marat O., E-mail: glm@spm.phys.msu.ru [Faculty of Physics, Lomonosov Moscow State University, Leninskie gory 1–2, Moscow 119991 (Russian Federation); Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova 28, Moscow 119991 (Russian Federation); Chaschin, Ivan S. [Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova 28, Moscow 119991 (Russian Federation); Khokhlova, Marina A. [Faculty of Physics, Lomonosov Moscow State University, Leninskie gory 1–2, Moscow 119991 (Russian Federation); Grigorev, Timofey E. [Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova 28, Moscow 119991 (Russian Federation); Bakuleva, Natalia P.; Lyutova, Irina G.; Kondratenko, Janna E. [Bakulev Scientific Center for Cardiovascular Surgery of the Russian Academy of Medical Sciences, Roublyevskoe Sh. 135, Moscow 121552 (Russian Federation); Badun, Gennadii A.; Chernysheva, Maria G. [Radiochemistry Division, Faculty of Chemistry, Lomonosov Moscow State University, Leninskie gory 1–2, Moscow 119991 (Russian Federation); Khokhlov, Alexei R. [Faculty of Physics, Lomonosov Moscow State University, Leninskie gory 1–2, Moscow 119991 (Russian Federation); Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova 28, Moscow 119991 (Russian Federation)

    2014-04-01

    Calcification of bovine pericardium dramatically shortens typical lifetimes of biological prosthetic heart valves and thus precludes their choice for younger patients. The aim of the present work is to demonstrate that the calcification is to be mitigated by means of treatment of bovine pericardium in solutions of chitosan in carbonic acid, i.e. water saturated with carbon dioxide at high pressure. This acidic aqueous fluid unusually combines antimicrobial properties with absolute biocompatibility as far as at normal pressure it decomposes spontaneously and completely into H{sub 2}O and CO{sub 2}. Yet, at high pressures it can protonate and dissolve chitosan materials with different degrees of acetylation (in the range of 16–33%, at least) without any further pretreatment. Even exposure of the bovine pericardium in pure carbonic acid solution without chitosan already favours certain reduction in calcification, somewhat improved mechanical properties, complete biocompatibility and evident antimicrobial activity of the treated collagen tissue. The reason may be due to high extraction ability of this peculiar compressed fluidic mixture. Moreover, exposure of the bovine pericardium in solutions of chitosan in carbonic acid introduces even better mechanical properties and highly pronounced antimicrobial activity of the modified collagen tissue against adherence and biofilm formation of relevant Gram-positive and Gram-negative strains. Yet, the most important achievement is the detected dramatic reduction in calcification for such modified collagen tissues in spite of the fact that the amount of the thus introduced chitosan is rather small (typically ca. 1 wt.%), which has been reliably detected using original tritium labelling method. We believe that these improved properties are achieved due to particularly deep and uniform impregnation of the collagen matrix with chitosan from its pressurised solutions in carbonic acid. - Highlights: • Treatment of GA

  14. Improved mucoadhesion and cell uptake of chitosan and chitosan oligosaccharide surface-modified polymer nanoparticles for mucosal delivery of proteins.

    Science.gov (United States)

    Dyawanapelly, Sathish; Koli, Uday; Dharamdasani, Vimisha; Jain, Ratnesh; Dandekar, Prajakta

    2016-08-01

    The main aim of the present study was to compare mucoadhesion and cellular uptake efficiency of chitosan (CS) and chitosan oligosaccharide (COS) surface-modified polymer nanoparticles (NPs) for mucosal delivery of proteins. We have developed poly (D, L-lactide-co-glycolide) (PLGA) NPs, surface-modified COS-PLGA NPs and CS-PLGA NPs, by using double emulsion solvent evaporation method, for encapsulating bovine serum albumin (BSA) as a model protein. Surface modification of NPs was confirmed using physicochemical characterization methods such as particle size and zeta potential, SEM, TEM and FTIR analysis. Both surface-modified PLGA NPs displayed a slow release of protein compared to PLGA NPs. Furthermore, we have explored the mucoadhesive property of COS as a material for modifying the surface of polymeric NPs. During in vitro mucoadhesion test, positively charged COS-PLGA NPs and CS-PLGA NPs exhibited enhanced mucoadhesion, compared to negatively charged PLGA NPs. This interaction was anticipated to improve the cell interaction and uptake of NPs, which is an important requirement for mucosal delivery of proteins. All nanoformulations were found to be safe for cellular delivery when evaluated in A549 cells. Moreover, intracellular uptake behaviour of FITC-BSA loaded NPs was extensively investigated by confocal laser scanning microscopy and flow cytometry. As we hypothesized, positively charged COS-PLGA NPs and CS-PLGA NPs displayed enhanced intracellular uptake compared to negatively charged PLGA NPs. Our results demonstrated that CS- and COS-modified polymer NPs could be promising carriers for proteins, drugs and nucleic acids via nasal, oral, buccal, ocular and vaginal mucosal routes. PMID:27106502

  15. Hydrogen sulfide donor sodium hydrosulfide-improved heat tolerance in maize and involvement of proline.

    Science.gov (United States)

    Li, Zhong-Guang; Ding, Xiao-Jiao; Du, Pei-Fang

    2013-05-15

    Hydrogen sulfide (H2S) has long been considered as a phytotoxin, but nowadays as a cell signal molecule involved in growth, development, and the acquisition of stress tolerance in higher plants. In the present study, hydrogen sulfide donor, sodium hydrosulfide (NaHS), pretreatment markedly improved germination percentage of seeds and survival percentage of seedlings of maize under heat stress, and alleviated an increase in electrolyte leakage of roots, a decrease in tissue vitality and an accumulation of malondialdehyde (MDA) in coleoptiles of maize seedlings. In addition, pretreatment of NaHS could improve the activity of Δ(1)-pyrroline-5-carboxylate synthetase (P5CS) and lower proline dehydrogenase (ProDH) activity, which in turn induced accumulation of endogenous proline in maize seedlings. Also, application of proline could enhance endogenous proline content, followed by mitigated accumulation of MDA and increased survival percentage of maize seedlings under heat stress. These results suggest that sodium hydrosulfide pretreatment could improve heat tolerance of maize and the acquisition of this heat tolerance may be involved in proline.

  16. Improved tolerance of maize (Zea mays L.) to heavy metals by colonization of a dark septate endophyte (DSE) Exophiala pisciphila

    Energy Technology Data Exchange (ETDEWEB)

    Li, T.; Liu, M.J.; Zhang, X.T. [Key Laboratory of Conservation and Utilization for Bioresources, Yunnan University, Kunming, 650091 Yunnan (China); Zhang, H.B. [Key Laboratory of Conservation and Utilization for Bioresources, Yunnan University, Kunming, 650091 Yunnan (China); Department of Biology, Yunnan University, Kunming, 650091 Yunnan (China); Sha, T. [Key Laboratory of Conservation and Utilization for Bioresources, Yunnan University, Kunming, 650091 Yunnan (China); Zhao, Z.W., E-mail: zhaozhw@ynu.edu.cn [Key Laboratory of Conservation and Utilization for Bioresources, Yunnan University, Kunming, 650091 Yunnan (China)

    2011-02-15

    Dark septate endophytes (DSE) are ubiquitous and abundant in stressful environments including heavy metal (HM) stress. However, our knowledge about the roles of DSE in improving HM tolerance of their host plants is poor. In this study, maize (Zea mays L.) was inoculated with a HM tolerant DSE strain Exophiala pisciphila H93 in lead (Pb), zinc (Zn), and cadmium (Cd) contaminated soils. E. pisciphila H93 successfully colonized and formed typical DSE structures in the inoculated maize roots. Colonization of E. pisciphila H93 alleviated the deleterious effects of excessive HM supplements and promoted the growth of maize (roots and shoots) under HM stress conditions, though it significantly decreased the biomass of inoculated maize under no HM stress. Further analysis showed that the colonization of E. pisciphila H93 improved the tolerance of maize to HM by restricting the translocation of HM ions from roots to shoots. This study demonstrated that under higher HM stress, such a mutual symbiosis between E. pisciphila and its host (maize) may be an efficient strategy to survive in the stressful environments. - Research Highlights: {yields}Effect of DSE (E. pisciphila) on heavy metal tolerance of maize host was studied. {yields}DSE alleviated the deleterious effect of excessive heavy metals on maize. {yields}DSE restricted the transfer of heavy metals from the roots to shoots in maize. {yields}DSE colonization improved the tolerance of their host plants to heavy metals.

  17. Chitosan functional properties.

    Science.gov (United States)

    Shepherd, R; Reader, S; Falshaw, A

    1997-06-01

    Chitosan is a partially deacetylated polymer of N-acetyl glucosamine. It is essentially a natural, water-soluble, derivative of cellulose with unique properties. Chitosan is usually prepared from chitin (2 acetamido-2-deoxy beta-1,4-D-glucan) and chitin has been found in a wide range of natural sources (crustaceans, fungi, insects, annelids, molluscs, coelenterata etc.) However chitosan is only manufactured from crustaceans (crab and crayfish) primarily because a large amount of the crustacean exoskeleton is available as a by product of food processing. Squid pens (a waste byproduct of New Zealand squid processing) are a novel, renewable source of chitin and chitosan. Squid pens are currently regarded as waste and so the raw material is relatively cheap. This study was intended to assess the functional properties of squid pen chitosan. Chitosan was extracted from squid pens and assessed for composition, rheology, flocculation, film formation and antimicrobial properties. Crustacean chitosans were also assessed for comparison. Squid chitosan was colourless, had a low ash content and had significantly improved thickening and suspending properties. The flocculation capacity of squid chitosan was low in comparison with the crustacean sourced chitosans. However it should be possible to increase the flocculation capacity of squid pen chitosan by decreasing the degree of acetylation. Films made with squid chitosan were more elastic than crustacean chitosan with improved functional properties. This high quality chitosan could prove particularly suitable for medical/analytical applications.

  18. Seed priming improves early seedling vigor, growth and productivity of spring maize

    Institute of Scientific and Technical Information of China (English)

    Hafeez ur Rehman[1; Hassan lqbal[1; Shahzad M A Basra[1; Irfan Afzal[1; Muhammad Farooq[2; Abdul Wakeel[3; WANG Ning[4

    2015-01-01

    Potential of seed priming treatments in improving the performance of early planted maize was evaluated against timely planting. Seeds of maize hybrid FH-810 were soaked in water (hydropriming), CaCI2 (2.2%, osmopriming), moringa leaf extracts (MLE 3.3%, osmopriming) and salicylic acid (SA, 50 mg L-1, hormonal priming) each for 18 h. Untreated and hydroprimed seeds were taken as control. Seeds primed with SA took less time in emergence and had high vigor in eady planted maize. Amongst treatments, hormonal priming, reduced the electrical conductivity, increased the leaf relative and chlorophyll contents followed by osmopriming with CaCI2 at seedling stage. Likewise, plant height, grain rows and 1 000-grain weight, grain and biological yield and harvest index were also improved by seed pdming; however hormonal priming and osmopriming with MLE were more effective in this regard. Improved yield performance by hormonal priming or osmopriming with MLE in early planting primarily owed to increased leaf area index, crop growth and net assimilation rates, and maintenance of green leaf area at maturity. In conclusion, osmopriming with MLE and hormonal priming with SA were the most economical treatments in improving productivity of early planted spring maize through stimulation of early seedling growth at low temperature.

  19. Seed priming improves early seedling vigor, growth and productivity of spring maize

    Institute of Scientific and Technical Information of China (English)

    Hafeez ur Rehman; Hassan Iqbal; Shahzad M A Basra; Irfan Afzal; Muhammad Farooq; Abdul Wakeel; WANG Ning

    2015-01-01

    Potential of seed priming treatments in improving the performance of early planted maize was evaluated against timely planting. Seeds of maize hybrid FH-810 were soaked in water (hydropriming), CaCl2 (2.2%, osmopriming), moringa leaf extracts (MLE 3.3%, osmopriming) and salicylic acid (SA, 50 mg L–1, hormonal priming) each for 18 h. Untreated and hydroprimed seeds were taken as control. Seeds primed with SA took less time in emergence and had high vigor in early planted maize. Amongst treatments, hormonal priming, reduced the electrical conductivity, increased the leaf relative and chlorophyl contents fol owed by osmopriming with CaCl2 at seedling stage. Likewise, plant height, grain rows and 1 000-grain weight, grain and biological yield and harvest index were also improved by seed priming;however hormonal priming and osmopriming with MLE were more effective in this regard. Improved yield performance by hormonal priming or osmopriming with MLE in early planting primarily owed to increased leaf area index, crop growth and net assimilation rates, and maintenance of green leaf area at maturity. In conclusion, osmopriming with MLE and hormonal priming with SA were the most economical treatments in improving productivity of early planted spring maize through stimulation of early seedling growth at low temperature.

  20. Conservation agriculture practices in rainfed uplands of India improve maize-based system productivity and profitability

    Directory of Open Access Journals (Sweden)

    Aliza Pradhan

    2016-07-01

    Full Text Available Traditional agriculture in rainfed uplands of India has been experiencing low agricultural productivity as the lands suffer from poor soil fertility, susceptibility to water erosion and other external pressures of development and climate change. A shift towards more sustainable cropping systems such as conservation agriculture production systems (CAPS may help in maintaining soil quality as well as improving crop production and farmer’s net economic benefit. This research assessed the effects over three years (2011-2014 of reduced tillage, intercropping, and cover cropping practices customized for maize-based production systems in upland areas of Odisha, India. The study focused on crop yield, system productivity and profitability through maize equivalent yield and dominance analysis. Results showed that maize grain yield did not differ significantly over time or among CAPS treatments while cowpea yield was considered as an additional yield in intercropping systems. Mustard and horsegram grown in plots after maize cowpea intercropping recorded higher grain yields of 25 and 37%, respectively, as compared to those without intercropping. Overall, the full CAPS implementation i.e. minimum tillage, maize-cowpea intercropping and mustard residue retention had significantly higher system productivity and net benefits than traditional farmer practices, i.e. conventional tillage, sole maize cropping, and no mustard residue retention. The dominance analysis demonstrated increasing benefits of combining conservation practices that exceeded thresholds for farmer adoption. Given the use of familiar crops and technologies and the magnitude of yield and income improvements, these types of CAPS should be acceptable and attractive for smallholder farmers in the area. This in turn should support a move toward sustainable intensification of crop production to meet future household income and nutritional needs.

  1. Conservation Agriculture Practices in Rainfed Uplands of India Improve Maize-Based System Productivity and Profitability.

    Science.gov (United States)

    Pradhan, Aliza; Idol, Travis; Roul, Pravat K

    2016-01-01

    Traditional agriculture in rainfed uplands of India has been experiencing low agricultural productivity as the lands suffer from poor soil fertility, susceptibility to water erosion and other external pressures of development and climate change. A shift toward more sustainable cropping systems such as conservation agriculture production systems (CAPSs) may help in maintaining soil quality as well as improving crop production and farmer's net economic benefit. This research assessed the effects over 3 years (2011-2014) of reduced tillage, intercropping, and cover cropping practices customized for maize-based production systems in upland areas of Odisha, India. The study focused on crop yield, system productivity and profitability through maize equivalent yield and dominance analysis. Results showed that maize grain yield did not differ significantly over time or among CAPS treatments while cowpea yield was considered as an additional yield in intercropping systems. Mustard and horsegram grown in plots after maize cowpea intercropping recorded higher grain yields of 25 and 37%, respectively, as compared to those without intercropping. Overall, the full CAPS implementation, i.e., minimum tillage, maize-cowpea intercropping and mustard residue retention had significantly higher system productivity and net benefits than traditional farmer practices, i.e., conventional tillage, sole maize cropping, and no mustard residue retention. The dominance analysis demonstrated increasing benefits of combining conservation practices that exceeded thresholds for farmer adoption. Given the use of familiar crops and technologies and the magnitude of yield and income improvements, these types of CAPS should be acceptable and attractive for smallholder farmers in the area. This in turn should support a move toward sustainable intensification of crop production to meet future household income and nutritional needs.

  2. Conservation Agriculture Practices in Rainfed Uplands of India Improve Maize-Based System Productivity and Profitability.

    Science.gov (United States)

    Pradhan, Aliza; Idol, Travis; Roul, Pravat K

    2016-01-01

    Traditional agriculture in rainfed uplands of India has been experiencing low agricultural productivity as the lands suffer from poor soil fertility, susceptibility to water erosion and other external pressures of development and climate change. A shift toward more sustainable cropping systems such as conservation agriculture production systems (CAPSs) may help in maintaining soil quality as well as improving crop production and farmer's net economic benefit. This research assessed the effects over 3 years (2011-2014) of reduced tillage, intercropping, and cover cropping practices customized for maize-based production systems in upland areas of Odisha, India. The study focused on crop yield, system productivity and profitability through maize equivalent yield and dominance analysis. Results showed that maize grain yield did not differ significantly over time or among CAPS treatments while cowpea yield was considered as an additional yield in intercropping systems. Mustard and horsegram grown in plots after maize cowpea intercropping recorded higher grain yields of 25 and 37%, respectively, as compared to those without intercropping. Overall, the full CAPS implementation, i.e., minimum tillage, maize-cowpea intercropping and mustard residue retention had significantly higher system productivity and net benefits than traditional farmer practices, i.e., conventional tillage, sole maize cropping, and no mustard residue retention. The dominance analysis demonstrated increasing benefits of combining conservation practices that exceeded thresholds for farmer adoption. Given the use of familiar crops and technologies and the magnitude of yield and income improvements, these types of CAPS should be acceptable and attractive for smallholder farmers in the area. This in turn should support a move toward sustainable intensification of crop production to meet future household income and nutritional needs. PMID:27471508

  3. 3D chitosan-gelatin-chondroitin porous scaffold improves osteogenic differentiation of mesenchymal stem cells

    Energy Technology Data Exchange (ETDEWEB)

    Machado, C B [Department of Biochemistry and Immunology, Institute of Biological Sciences, Federal University of Minas Gerais (Brazil); Ventura, J M G [Department of Ceramics and Glass Engineering, University of Aveiro (Portugal); Lemos, A F [Department of Ceramics and Glass Engineering, University of Aveiro (Portugal); Ferreira, J M F [Department of Ceramics and Glass Engineering, University of Aveiro (Portugal); Leite, M F [Department of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais (Brazil); Goes, A M [Department of Biochemistry and Immunology, Institute of Biological Sciences, Federal University of Minas Gerais (Brazil)

    2007-06-01

    A porous 3D scaffold was developed to support and enhance the differentiation process of mesenchymal stem cells (MSC) into osteoblasts in vitro. The 3D scaffold was made with chitosan, gelatin and chondroitin and it was crosslinked by EDAC. The scaffold physicochemical properties were evaluated. SEM revealed the high porosity and interconnection of pores in the scaffold; rheological measurements show that the scaffold exhibits a characteristic behavior of strong gels. The elastic modulus found in compressive tests of the crosslinked scaffold was about 50 times higher than the non-crosslinked one. After 21 days, the 3D matrix submitted to hydrolytic degradation loses above 40% of its weight. MSC were collected from rat bone marrow and seeded in chitosan-gelatin-chondroitin 3D scaffolds and in 2D culture plates as well. MSC were differentiated into osteoblasts for 21 days. Cell proliferation and alkaline phosphatase activity were followed weekly during the osteogenic process. The osteogenic differentiation of MSC was improved in 3D culture as shown by MTT assay and alkaline phosphatase activity. On the 21st day, bone markers, osteopontin and osteocalcin, were detected by the PCR analysis. This study shows that the chitosan-gelatin-chondroitin 3D structure provides a good environment for the osteogenic process and enhances cellular proliferation.

  4. Prosopis alba exudate gum as excipient for improving fish oil stability in alginate-chitosan beads.

    Science.gov (United States)

    Vasile, Franco Emanuel; Romero, Ana María; Judis, María Alicia; Mazzobre, María Florencia

    2016-01-01

    The aim of the present work was to employ an exudate gum obtained from a South American wild tree (Prosopis alba), as wall material component to enhance the oxidative stability of fish oil encapsulated in alginate-chitosan beads. For this purpose, beads were vacuum-dried and stored under controlled conditions. Oxidation products, fatty acid profiles and lipid health indices were measured during storage. Alginate-chitosan interactions and the effect of gum were manifested in the FT-IR spectra. The inclusion of the gum in the gelation media allowed decreasing the oxidative damage during storage in comparison to the free oil and alginate-chitosan beads. The gum also improved wall material properties, providing higher oil retention during the drying step and subsequent storage. Fatty acids quality and lipid health indices were widely preserved in beads containing the gum. Present results showed a positive influence of the gum on oil encapsulation and stability, being the main mechanism attributed to a physical barrier effect.

  5. Increased grain yield with improved photosynthetic characters in modern maize parental lines

    Institute of Scientific and Technical Information of China (English)

    LI Cong-feng[1; TAO Zhi-qiang[1; LIU Peng[2; ZHANG Ji-wang[2; ZHUANG Ke-zhang[3; DONG Shu-ting[2; ZHAO Ming[1

    2015-01-01

    The grain yield of maize has increased continuously in past decades, largely through hybrid innovation, cultivation tech- nology, and in particular, recent genetic improvements in photosynthesis. Elite inbred lines are crucial for innovating new germplasm. Here, we analyzed variations in grain yield and a series of eco-physiological photosynthetic traits after anthesis in sixteen parental lines of maize (Zea mays L.) released during three different eras (1960s, 1980s, 2000s). We found that grain yield and biomass significantly increased in the 2000s than those in the 1980s and 1960s. Leaf area, chlorophyll, and soluble protein content slowly decreased, and maintained a higher net photosynthesis rate (Po) and improved stomatal conductance (Gs) after anthesis in the 2000s. In addition, the parental lines in the 2000s obtained higher actual photo- chemistry efficiency (Ps,) and the maximum PSII photochemistry efficiency (FJFm), which largely improved light partition- ing and chlorophyll fluorescence characteristic, including higher photochemical and photosystem II (PSII) reaction center activity, lower thermal energy dissipation in antenna proteins. Meanwhile, more lamellae per granum within chloroplasts were observed in the parental lines of the 2000s, with a clear and complete chloroplast membrane, which will greatly help to improve photosynthetic capacity and energy efficiency of ear leaf in maize parental lines. It is concluded that grain yield increase in modern maize parental lines is mainly attributed to the improved chloroplast structure and more light energy catched for the photochemical reaction, thus having a better stay-green characteristic and stronger photosynthetic capac- ity after anthesis. Our direct physiological evaluation of these inbred lines provides important information for the further development of promising maize cultivars.

  6. Chitosan Coagulation to Improve Microbial and Turbidity Removal by Ceramic Water Filtration for Household Drinking Water Treatment.

    Science.gov (United States)

    Abebe, Lydia S; Chen, Xinyu; Sobsey, Mark D

    2016-03-01

    The use of porous ceramic filters is promoted globally for household water treatment, but these filters are ineffective in removing viruses from water. In order to increase virus removal, we combine a promising natural coagulant, chitosan, as a pretreatment for ceramic water filters (CWFs) and evaluate the performance of this dual barrier water treatment system. Chitosan is a non-toxic and biodegradable organic polymer derived by simple chemical treatments from chitin, a major source of which is the leftover shells of crustacean seafoods, such as shrimp, prawns, crabs, and lobsters. To determine the effectiveness of chitosan, model test water was contaminated with Escherichia coli K011 and coliphage MS2 as a model enteric bacterium and virus, respectively. Kaolinite clay was used to model turbidity. Coagulation effectiveness of three types of modified chitosans was determine at various doses ranging from 5 to 30 mg/L, followed by flocculation and sedimentation. The pre-treated supernatant water was then decanted into the CWF for further treatment by filtration. There were appreciable microbial removals by chitosan HCl, acetate, and lactate pretreatment followed by CWF treatment, with mean reductions (95% CI) between 4.7 (± 1.56) and 7.5 (± 0.02) log10 for Escherichia coli, and between 2.8 (± 0.10) and 4.5 (± 1.04) log10 for MS2. Turbidity reduction with chitosan treatment and filtration consistently resulted in turbidities water treatment technology, chitosan coagulation achieved health protective targets for both viruses and bacteria. Therefore, the results of this study support the use of chitosan to improve household drinking water filtration processes by increasing virus and bacteria reductions.

  7. Chitosan Coagulation to Improve Microbial and Turbidity Removal by Ceramic Water Filtration for Household Drinking Water Treatment

    Directory of Open Access Journals (Sweden)

    Lydia S. Abebe

    2016-02-01

    Full Text Available The use of porous ceramic filters is promoted globally for household water treatment, but these filters are ineffective in removing viruses from water. In order to increase virus removal, we combine a promising natural coagulant, chitosan, as a pretreatment for ceramic water filters (CWFs and evaluate the performance of this dual barrier water treatment system. Chitosan is a non-toxic and biodegradable organic polymer derived by simple chemical treatments from chitin, a major source of which is the leftover shells of crustacean seafoods, such as shrimp, prawns, crabs, and lobsters. To determine the effectiveness of chitosan, model test water was contaminated with Escherichia coli K011 and coliphage MS2 as a model enteric bacterium and virus, respectively. Kaolinite clay was used to model turbidity. Coagulation effectiveness of three types of modified chitosans was determine at various doses ranging from 5 to 30 mg/L, followed by flocculation and sedimentation. The pre-treated supernatant water was then decanted into the CWF for further treatment by filtration. There were appreciable microbial removals by chitosan HCl, acetate, and lactate pretreatment followed by CWF treatment, with mean reductions (95% CI between 4.7 (±1.56 and 7.5 (±0.02 log10 for Escherichia coli, and between 2.8 (±0.10 and 4.5 (±1.04 log10 for MS2. Turbidity reduction with chitosan treatment and filtration consistently resulted in turbidities < 1 NTU, which meet turbidity standards of the US EPA and guidance by the World Health Organization (WHO. According to WHO health-based microbial removal targets for household water treatment technology, chitosan coagulation achieved health protective targets for both viruses and bacteria. Therefore, the results of this study support the use of chitosan to improve household drinking water filtration processes by increasing virus and bacteria reductions.

  8. Analysis of Participatory Research Projects in the International Maize and Wheat Improvement Center

    OpenAIRE

    Lilja, Nina K.; Bellon, Mauricio R.

    2006-01-01

    Through a survey of scientists from the International Maize and Wheat Improvement Center (CIMMYT) in 2004, this study assessed the extent to which participatory methods had been used by the center, how they were perceived by the scientists, and how participatory research could be applied more effectively by CIMMYT and partners. Results for 19 CIMMYT projects suggest among other things that participatory approaches at the center were largely “functional”—that is, aimed at improving the efficie...

  9. Improvement of the soil nitrogen content and maize growth by earthworms and arbuscular mycorrhizal fungi in soils polluted by oxytetracycline.

    Science.gov (United States)

    Cao, Jia; Wang, Chong; Ji, Dingge

    2016-11-15

    Interactions between earthworms (Eisenia fetida) and arbuscular mycorrhizal fungi (Rhizophagus intraradices, AM fungi) have been suggested to improve the maize nitrogen (N) content and biomass and were studied in soils polluted by oxytetracycline (OTC). Maize was planted and amended with AMF and/or earthworms (E) in the soil with low (1mgkg(-1) soil DM) or high (100mgkg(-1) soil DM) amounts of OTC pollution in comparison to soil without OTC. The root colonization, shoot and root biomass, shoot and root N contents, soil nitrogen forms, ammonia-oxidizing bacteria (AOB) and archaea (AOA) were measured at harvest. The results indicated that OTC decreased maize shoot and root biomass (pfungi on the urease activity in soil polluted by OTC (pfungi could increase the maize biomass and N content (pfungi and earthworms interactively increased maize shoot and root biomass (pfungi could be used as an efficient method to relieve the OTC stress in agro-ecosystems. PMID:27496075

  10. Farm technology adoption in Kenya: A simultaneous estimation of inorganic fertilizer and improved maize variety adoption decisions

    OpenAIRE

    Ogada, Maurice J.; Mwabu, Germano; Muchai, Diana

    2014-01-01

    This paper models inorganic fertilizer and improved maize varieties adoption as joint decisions. Controlling for household, plot-level, institutional and other factors, the study found that household adoption decisions on inorganic fertilizer and improved maize varieties were inter-dependent. Other factors found to influence the adoption of the two technologies were farmer characteristics, plot-level factors and market imperfections such as limited access to credit and input markets, and prod...

  11. Silicon induced improvement in morpho-physiological traits of maize (zea mays l.) under water deficit

    International Nuclear Information System (INIS)

    Current water scarcity is an emerging issue in semi-arid regions like Pakistan and cause of deterioration in productivity of crops to reduce crop yield all over the world. Silicon is known to be better against the deleterious effects of drought on plant growth and development. A pot study was conducted to evaluate the effect of Si nutrition (0, 50, 100 and 150 mg/kg) on the growth of a relatively drought tolerant (P-33H25) and sensitive (FH-810) maize hybrids. Two levels of soil water content were used viz. 100 and 60% of field capacity. Water deficit condition in soil significantly reduced morphological and physiological attributes of maize plants. Silicon application significantly improved the plant height, leaf area per plant, primary root length, dry matter of shoot and roots and plant dry matter, water relation and gas exchange characteristics of both maize cultivars under water deficit condition. Poor growth of drought stressed plants was significantly improved with Si application. The silicon fertilized (100 mg/kg) drought stressed plants of hybrid P-33H25 produced maximum (21.68% more) plant dry matter as compared to plants that were not provided with silicon nutrition. Nonetheless, silicon application (150 mg/kg) resulted in maximum increase (26.03%) in plant dry weight of hybrid FH-810 plants that were grown under limited moisture supply i.e., 60% FC. In conclusion silicon application to drought stressed maize plants was better to improve the growth and dry matter could be attributed to improved osmotic adjustment, photosynthetic rate and lowered transpiration. (author)

  12. Improvement in physical and biological properties of chitosan/soy protein films by surface grafted heparin.

    Science.gov (United States)

    Wang, Xiaomei; Hu, Ling; Li, Chen; Gan, Li; He, Meng; He, Xiaohua; Tian, Weiqun; Li, Mingming; Xu, Li; Li, Yinping; Chen, Yun

    2016-02-01

    A series of chitosan/soy protein isolate (SPI) composite films (CS-n, n=0, 10 and 30, corresponding to SPI content in the composites) were prepared. Heparin was grafted onto the surface of CS-n to fabricate a series of heparinized films (HCS-n). CS-n and HCS-n were characterized by ATR-Fourier transform infrared spectroscopy and water contact angle. The surface heparin density was measured by toluidine blue assay. The results showed that heparin has been successfully grafted onto the surface of CS-n. Heparin evenly distributed on the surface of the films and the heparin content increased with the increase of SPI content, and the hydrophilicity of the films was enhanced due to the grafted heparin. The cytocompatibility and hemocompatibility of CS-n and HCS-n were evaluated by cell culture (MTT assay, live/dead assay, cell morphology and cell density observation), platelet adhesion test, plasma recalcification time (PRT) measurement, hemolysis assay and thrombus formation test. HCS-n showed higher cell adhesion rate and improved cytocompatibility compared to the corresponding CS-n. HCS-n also exhibited lower platelet adhesion, longer PRT, higher blood anticoagulant indexes (BCI) and lower hemolysis rate than the corresponding CS-n. The improved cytocompatibility and hemocompatibility of HCS-n would shed light on the potential applications of chitosan/soy protein-based biomaterials that may come into contact with blood.

  13. The effects of improved maize technology on household welfare in Buruku, Benue State, Nigeria

    Directory of Open Access Journals (Sweden)

    Victoria I. Audu

    2014-12-01

    Full Text Available This study was carried out to determine the welfare effects of improved maize technology in Buruku Local Government Area of Benue State, Nigeria. The study also examined the determinants of the adoption of improved maize technology. Structured questionnaires were used in collecting the primary data for the study. A multi-stage random technique was used in selecting 125 farm households for the study. The Logit and ordinary least square (OLS models were used in analyzing the data. The OLS results show that adoption of improved maize varieties is positively and significantly related to household welfare and thus has contributed to moving farm households out of poverty. Other variables found to be statistically significant in explaining household welfare are education, household size, and landholding. The Logit results show that age, household size, off-farm income, and education were found to be significant in influencing farmers’ adoption decisions. Some robustness checks were performed with different specifications of the Logit and OLS models as well as re-estimation with propensity matching score approach. Overall, the results are robust to different specifications.

  14. Improved postharvest quality in patagonian squash (Cucurbita moschata) coated with radiation depolymerized chitosan

    Energy Technology Data Exchange (ETDEWEB)

    Pugliese, Maria Alicia; Goitia, Maria Teresa [Laboratorio de Investigaciones Basicas Aplicadas en Quitina, Departamento de Quimica, Universidad Nacional del Sur. Avenida Alem 1253, B8000CPB Bahia Blanca (Argentina); Yossen, Mariana [Instituto de Desarrollo Tecnologico para la Industria Quimica (INTEC), CONICET-Universidad Nacional del Litoral, Ruta Nacional 168-Paraje ' El Pozo' , 3000 Santa Fe (Argentina); Cifone, Norma; Agullo, Enrique [Laboratorio de Investigaciones Basicas Aplicadas en Quitina, Departamento de Quimica, Universidad Nacional del Sur. Avenida Alem 1253, B8000CPB Bahia Blanca (Argentina); Andreucetti, Noemi, E-mail: andreuce@criba.edu.ar [Laboratorio de Radioisotopos, Departamento de Quimica, Universidad Nacional del Sur, Avenida Alem 1253, B8000CPB Bahia Blanca (Argentina)

    2011-12-15

    Different molecular weight chitosans were evaluated on the decay of coated Anquito squashes (Cucurbita moschata) as well as the maintenance of the fruit quality along five storage months. The original chitosan (Mw=391 kDa, 83% DD), was depolymerized by gamma radiation. Apart from chain scission, other chemical changes were not detected by FTIR or UV-vis analyses. The molecular weight characterization of chitosans was done by size exclusion chromatography with dual light scattering and concentration detection (SEC-MALLS-RI). The coating effectiveness was evaluated on the following parameters: fungal decay incidence, weight loss, firmness, total reducing sugar, soluble solid, flesh color, carotene content, pH and titratable acidity. No sign of fungal decay was observed in squashes coated with 122 and 56 kDa chitosans, which were also the most effective treatments in reducing the weight loss. The chitosan with Mw=122 kDa was also the best treatment considering firmness, internal aspect, sugar and carotene content. Then, radiation degraded chitosan was better in C. moschata preservation than the original chitosan. - Highlights: > Original Chitosan was radiation depolymerized producing chitosans with lower molecular weights. > Gamma-irradiated chitosans only exhibit chain scission. > SEC-MALLS-RI chromatography is a useful tool in molecular weight analysis. > Depolymerized chitosans were the best in maintaining the quality and the storage life of coated squashes.

  15. Amendment of Tephrosia Improved Fallows with Inorganic Fertilizers Improves Soil Chemical Properties, N Uptake, and Maize Yield in Malawi

    Directory of Open Access Journals (Sweden)

    Maggie G. Munthali

    2014-01-01

    Full Text Available Maize production in Malawi is limited mainly by low soil N and P. Improved fallows of N-fixing legumes such as Tephrosia and Sesbania offer options for improving soil fertility particularly N supply. The interactions of Tephrosia fallows and inorganic fertilizers on soil properties, N uptake, and maize yields were evaluated at Chitedze Research Station in Malawi. The results indicated that the level of organic matter and pH increased in all the treatments except for the control. Total N remained almost unchanged while available P decreased in all plots amended with T. vogelii but increased in T. candida plots where inorganic P was applied. Exchangeable K increased in all the plots irrespective of the type of amendment. The interaction of N and P fertilizers with T. vogelii fallows significantly increased the grain yield. The treatment that received 45 kg N ha−1 and 20 kg P ha−1 produced significantly higher grain yields (6.8 t ha−1 than all the other treatments except where 68 kg N ha−1 and 30 kg P ha−1 were applied which gave 6.5 t ha−1 of maize grain. T. candida fallows alone or in combination with N and P fertilizers did not significantly affect grain yield. However, T. candida fallows alone can raise maize grain yield by 300% over the no-input control. Based on these results we conclude that high quality residues such as T. candida and T. vogelii can be used as sources of nutrients to improve crop yields and soil fertility in N-limited soils. However, inorganic P fertilizer is needed due to the low soil available P levels.

  16. Seed priming with chitosan improves the germination and growth performance of ajowan

    Directory of Open Access Journals (Sweden)

    Batool Mahdavi

    2013-11-01

    Full Text Available Background: Chitosan is a polysaccharide biopolymer derived from chitin. It not only stimulates growth and increases the crop yields but also alleviates the harmful effect of abiotic stress on plant growth. The objective of this study was to investigate the effects of chitosan on germination and growth of ajowan (Carum copticum under salt stress. This study was conducted in a laboratory and greenhouse. Material and Methods: In the first experiment seed germination of ajowan monitored under seed pre-treated by soaking in chitosan solutions of 0, 0.01%, 0.05%, 0.1%, 0.2% and 0.5% for 3 h. In second experiment, seeds soaked in chitosan solutions (0 and 0.2% and sown in pots at different salinity levels (0, 4, 8 and 12 dS/m. Results: Results indicated that all of chitosan concentrations increased germination percentage, germination rate, seedling vigour index, length and dry weight of hypocotyl and radicle compared to control although, 0.2% chitosan concentration was more effective than other treatments. Salinity caused a significant reduction in germination percentage, shoot length, root length, shoot and root dry weight and relative water content, while chitosan adjusted the salt toxicity. Conclusions: It is concluded that chitosan would be able to stimulate germination and growth of ajowan. It is also resulted that soaking ajowan seeds with chitosan, may alleviate the inhibitory effect of salt stress on the plant growth.

  17. Preparation of aminated chitosan/alginate scaffold containing halloysite nanotubes with improved cell attachment.

    Science.gov (United States)

    Amir Afshar, Hamideh; Ghaee, Azadeh

    2016-10-20

    The chemical nature of biomaterials play important role in cell attachment, proliferation and migration in tissue engineering. Chitosan and alginate are biodegradable and biocompatible polymers used as scaffolds for various medical and clinical applications. Amine groups of chitosan scaffolds play an important role in cell attachment and water adsorption but also associate with alginate carboxyl groups via electrostatic interactions and hydrogen bonding, consequently the activity of amine groups in the scaffold decreases. In this study, chitosan/alginate/halloysite nanotube (HNTs) composite scaffolds were prepared using a freeze-drying method. Amine treatment on the scaffold occurred through chemical methods, which in turn caused the hydroxyl groups to be replaced with carboxyl groups in chitosan and alginate, after which a reaction between ethylenediamine, 1-ethyl-3,(3-dimethylaminopropyl) carbodiimide (EDC) and scaffold triggered the amine groups to connect to the carboxyl groups of chitosan and alginate. The chemical structure, morphology and mechanical properties of the composite scaffolds were investigated by FTIR, CHNS, SEM/EDS and compression tests. The electrostatic attraction and hydrogen bonding between chitosan, alginate and halloysite was confirmed by FTIR spectroscopy. Chitosan/alginate/halloysite scaffolds exhibit significant enhancement in compressive strength compared with chitosan/alginate scaffolds. CHNS and EDS perfectly illustrate that amine groups were effectively introduced in the aminated scaffold. The growth and cell attachment of L929 cells as well as the cytotoxicity of the scaffolds were investigated by SEM and Alamar Blue (AB). The results indicated that the aminated chitosan/alginate/halloysite scaffold has better cell growth and cell adherence in comparison to that of chitosan/alginate/halloysite samples. Aminated chitosan/alginate/halloysite composite scaffolds exhibit great potential for applications in tissue engineering, ideally in

  18. Preparation of chitosan nanofiber tube by electrospinning.

    Science.gov (United States)

    Matsuda, Atsushi; Kagata, Go; Kino, Rikako; Tanaka, Junzo

    2007-03-01

    Water-insoluble chitosan nanofiber sheets and tubes coated with chitosan-cast film were prepared by electrospinning. When as-spun chitosan nanofiber sheets and tubes were immersed in 28% ammonium aqueous solution, they became insoluble in water and showed nanofiber structures confirmed by SEM micrography. Mechanical properties of chitosan nanofiber sheets and tubes were improved by coating with chitosan-cast film, which gave them a compressive strength higher than that of crab-tendon chitosan, demonstrating that chitosan nanofiber tubes coated with chitosan-cast film are usable as nerve-regenerative guide tubes.

  19. Potential of Using Manure to Improve Soil Fertility in A Maize/Bean Intercrop in the Drylands

    International Nuclear Information System (INIS)

    Low soil fertility as a limiting factor in maize and bean production in ASALS areas is a pertinent topic for investigation, owing to the importance of the crops as staple foods as well as sources of income and employment for the increasing population occasioned by high fertility rates and immigration from the congested high potential highlands. The use of readily available and cheaper sources of plant nutrients such as farm yard manure (FYM), under the common practice of intercropping is one way of sustaining agricultural production in the drylands. The objective of the study conducted in LM5 (under irrigation) and LM5 (under rainfed) Agro-ecological zones of Baringo district was to determine the potential of use FYM and bean intercropping to improve soil fertility for higher maize yields. The result showed that under maize pure stand the highest yields of 3.2 tons/ha were obtained under DAP though this was not significantly different with FYM, FYM+CAN and No Fertilizer treatments. Under intercrop the highest maize yields of 2.8 t/ha were obtained under FYM+CAN. Economic analysis showed that bean pure stand system gave the highest result net benefits followed by intercrop and lastly maize pure stand. The result further showed that the generally low crop yield coupled by low prices renders Katumani maize variety uneconomical to be grown under irrigation and that the higher yielding hybrids (eg H513 using FYM+CAN could be more profitable to farmers in both zones)

  20. Improvements of physical, mechanical and biodegradation properties of polybutadiene rubber insulators by chitosan and silica nanoparticles.

    Science.gov (United States)

    Saboktakin, Amin; Saboktakin, Mohammadreza

    2016-10-01

    1,4-cis-Polybutadiene rubber(1,4-cis pBR) as an insulation material is developing that will provide superior thermal insulation properties, flexibility, toughness by natural polymers such as chitosan(CS) and silica nanoparticles. This material is widely used in the insulation industries specially architecture. This research concerns physical, mechanical properties and also biodegradation of 1,4-cis pBR, which to be composed with the natural polymers such as CS. Silica nanoparticles were used as filler to improve the physical and mechanical properties of 1,4-cis pBR. To evaluating its physical and mechanical properties, stretching and bending and impact tests were used and the results show some improvement in these properties. Our observations show that temperature plays an important role as main factor in order to improve the mechanical properties of nanocomposites. Similar improvements in tensile modulus and strength have been observed for 1,4-cis pBR/CS-silica nanoparticles. PMID:27353394

  1. Discriminant analysis of farmers adoption of improved maize varieties in Wa Municipality, Upper West Region of Ghana.

    Science.gov (United States)

    Alhassan, Abukari; Salifu, Hussein; Adebanji, Atinuke O

    2016-01-01

    This study employed the quadratic classification function analysis to examine the influence of farmer's socio-demographic and varietal characteristics of maize on adoption of improved maize varieties (IMVs) in the Wa Municipality of the Upper West region of Ghana. The results showed that, farm labour, information availability about the variety, weed resistance, low yielding variety, early maturity and water stress resistance are the major discriminating variables in classifying farmers in the Municipality. The study however revealed that maize experience, low yield, information availability and cost of variety were the most influential discriminating variables between adopters and non-adopters of IMVs. The study recommended the need to improve on the level of farmers' education, ensure steady access to extension services and improvement in varietal characteristics identified in the study. PMID:27652087

  2. Reduced crown root number improves water acquisition under water deficit stress in maize (Zea mays L.).

    Science.gov (United States)

    Gao, Yingzhi; Lynch, Jonathan P

    2016-08-01

    In this study we test the hypothesis that maize genotypes with reduced crown root number (CN) will have greater root depth and improved water acquisition from drying soil. Maize recombinant inbred lines with contrasting CN were evaluated under water stress in greenhouse mesocosms and field rainout shelters. CN varied from 25 to 62 among genotypes. Under water stress in the mesocosms, genotypes with low CN had 31% fewer crown roots, 30% deeper rooting, 56% greater stomatal conductance, 45% greater leaf CO2 assimilation, 61% net canopy CO2 assimilation, and 55% greater shoot biomass than genotypes with high CN at 35 days after planting. Under water stress in the field, genotypes with low CN had 21% fewer crown roots, 41% deeper rooting, 48% lighter stem water oxygen isotope enrichment (δ(18)O) signature signifying deeper water capture, 13% greater leaf relative water content, 33% greater shoot biomass at anthesis, and 57% greater yield than genotypes with high CN. These results support the hypothesis that low CN improves drought tolerance by increasing rooting depth and water acquisition from the subsoil. PMID:27401910

  3. Improved postharvest quality in patagonian squash ( Cucurbita moschata) coated with radiation depolymerized chitosan

    Science.gov (United States)

    Pugliese, Maria Alicia; Goitia, Maria Teresa; Yossen, Mariana; Cifone, Norma; Agulló, Enrique; Andreucetti, Noemi

    2011-12-01

    Different molecular weight chitosans were evaluated on the decay of coated Anquito squashes ( Cucurbita moschata) as well as the maintenance of the fruit quality along five storage months. The original chitosan (Mw=391 kDa, 83% DD), was depolymerized by gamma radiation. Apart from chain scission, other chemical changes were not detected by FTIR or UV-vis analyses. The molecular weight characterization of chitosans was done by size exclusion chromatography with dual light scattering and concentration detection (SEC-MALLS-RI). The coating effectiveness was evaluated on the following parameters: fungal decay incidence, weight loss, firmness, total reducing sugar, soluble solid, flesh color, carotene content, pH and titratable acidity. No sign of fungal decay was observed in squashes coated with 122 and 56 kDa chitosans, which were also the most effective treatments in reducing the weight loss. The chitosan with Mw=122 kDa was also the best treatment considering firmness, internal aspect, sugar and carotene content. Then, radiation degraded chitosan was better in C. moschata preservation than the original chitosan.

  4. Improvement of antioxidant and antimicrobial activity of chitosan film with caraway and oregano essential oils

    Directory of Open Access Journals (Sweden)

    Hromiš Nevena M.

    2014-01-01

    Full Text Available In this work, caraway or oregano essential oils were added to the cast chitosan film in an attempt to design a natural, biodegradable, bioactive (antioxidant and antimicrobial packaging film. When the structure of the tested films was analyzed with Fourier transform infrared spectroscopy, no significant differences were found between the chitosan film with and without essential oils of caraway or oregano. The lowest antioxidant activity, based on the scavenging of the stable DPPH• free radical, was detected for the chitosan film without oil addition, going from 11.64%, after 2.5 h to 28.96%, after 24 h. When the caraway essential oil was added to the chitosan film, the antioxidant activity was increased (p<0.05 to 33.47±4.77%, after 2.5 h and to 81.08±0.64%, after 24 h. This increase in the antioxidant activity was even higher in the film with oregano essential oil (p<0.05. After 2.5 h, the value for the antioxidant activity of the chitosan-oregano film was 87.58±1.71%, and after 4 h and 24 h it was above 90%. The obtained results for the antimicrobial activity showed that the chitosan film is an effective antimicrobial agent against Escherichia coli and Staphylococcus aureus. When caraway essential oil was added in 1% volume concentration to the film, no increase in the antimicrobial action of chitosan film was detected. On the other hand, the addition of oregano essential oil promoted chitosan film antimicrobial activity, which was particularly evident with Escherichia coli. The results showed that the chitosan film can be successfully applied as a matrix carrier for essential oils in the active film system.[ Projekat Ministarstva nauke Republike Srbije, br. TR31032

  5. Characterization of Chitosan Nanofiber Sheets for Antifungal Application

    OpenAIRE

    Mayumi Egusa; Ryo Iwamoto; Hironori Izawa; Minoru Morimoto; Hiroyuki Saimoto; Hironori Kaminaka; Shinsuke Ifuku

    2015-01-01

    Chitosan produced by the deacetylation of chitin is a cationic polymer with antimicrobial properties. In this study, we demonstrate the improvement of chitosan properties by nanofibrillation. Nanofiber sheets were prepared from nanofibrillated chitosan under neutral conditions. The Young’s modulus and tensile strength of the chitosan NF sheets were higher than those of the chitosan sheets prepared from dissolving chitosan in acetic acid. The chitosan NF sheets showed strong mycelial growth in...

  6. Strategies to improve the aging, barrier and mechanical properties of chitosan, whey and wheat gluten protein films

    OpenAIRE

    Olabarrieta, Idoia

    2005-01-01

    Chitosan, Whey Protein Isolate (WPI) and vital wheat gluten (WG) are three biomaterials that have quite promising properties for packaging purposes. They have good film forming properties and good gas barrier properties in dry conditions. Moreover, because they are produced from industrial waste of food processing, they offer an ecological advantage over polymers made from petroleum. However, their physicochemical characteristics still must be improved for them to be of commercial interest fo...

  7. Physiological Strategies to Improve the Performance of Spring Maize (Zea mays L. Planted under Early and Optimum Sowing Conditions.

    Directory of Open Access Journals (Sweden)

    Muhammad Amir Bakhtavar

    Full Text Available Low temperature at stand establishment and high temperature at reproductive stage are involved in reduction of grain yield of spring maize. A field study was therefore conducted to evaluate different physiological strategies for improving performance of spring maize under temperature extremes. Seed priming and foliar spray with 3% moringa leaf extract (MLE and 100 mg L-1 kinetin solution alone or in all possible combinations with each other at three growth stages (knee height, tasseling and grain filling stage and hydropriming was compared with control. Seed priming plus foliar spray of MLE and kinetin significantly improved stand establishment especially under early sown crop as indicated by reduced mean emergence time (MET, improved emergence index (EI and final emergence percentage (FEP. Similarly increased chlorophyll contents, crop growth rate, leaf area index, photosynthetic rate, transpiration rate, relative water content and decreased membrane permeability were recorded in both early and optimum sowing conditions in MLE priming plus foliar spray treatment. All these improvements were harvested in the form of increased yield and harvest index compared with control treatment. Overall crop sown at optimum time performed best but exogenous application of MLE through seed priming and foliar spray maximally improved the performance of early sown maize crop which is attributed more likely due to improved stand establishment, chlorophyll and phenolic contents, increased leaf area duration and grain filling period. It can be concluded that seed priming with MLE along with its foliar spray could increase production of maize under temperature extremes.

  8. Survey of Genomics Approaches to Improve Bioenergy Traits in Maize, Sorghum and Sugarcane

    Institute of Scientific and Technical Information of China (English)

    Wilfred Vermerris

    2011-01-01

    Bioenergy crops currently provide the only source of alternative energy with the potential to reduce the use of fossil transportation fuels in a way that is compatible with existing engine technology, including in developing countries. Even though bioenergy research is currently receiving considerable attention, many of the concepts are not new,but rather build on intense research efforts from 30 years ago. A major difference with that era is the availability of genomics tools that have the potential to accelerate crop improvement significantly. This review is focused on maize, sorghum and sugarcane as representatives of bioenergy grasses that produce sugar and/or lignocellulosic biomass.Examples of how genetic mapping, forward and reverse genetics, high-throughput expression profiling and comparative genomics can be used to unravel and improve bioenergy traits will be presented.

  9. The alginate layer for improving doxorubicin release and radiolabeling stability of chitosan hydrogels

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Jeong Il; Lee, Chang Moon; Jeong, Hwan Seok; Hwang, Hyo Sook; Lim, Seok Tae; Sohn, Myung Hee; Jeong, Hwan Jeong [Dept. of Nuclear Medicine and Therapeutic Medicine Research Center, Cyclotron Research Center, Institute for Medical Science, Biomedical Research Institute, Chonbuk National University Medical School, Jeonju (Korea, Republic of); Lee, Chang Moon [Dept. of Biomedical Engineering, Chonnam National University, Yeosu (Korea, Republic of)

    2015-12-15

    Chitosan hydrogels (CSH) formed through ionic interaction with an anionic molecule are suitable as a drug carrier and a tissue engineering scaffold. However, the initial burst release of drugs from the CSH due to rapid swelling after immersing in a biofluid limits their wide application as a drug delivery carrier. In this study, alginate layering on the surface of the doxorubicin (Dox)-loaded and I-131-labeled CSH (DI-CSH) was performed. The effect of the alginate layering on drug release behavior and radiolabeling stability was investigated. Chitosan was chemically modified using a chelator for I-131 labeling. After labeling of I-131 and mixing of Dox, the chitosan solution was dropped into tripolyphosphate (TPP) solution using an electrospinning system to prepare spherical microhydrogels. The DI-CSH were immersed into alginate solution for 30 min to form the crosslinking layer on their surface. The formation of alginate layer on the DI-CSH was confirmed by Fourier transform infrared spectroscopy (FT-IR) and zeta potential analysis. In order to investigate the effect of alginate layer, studies of in vitro Dox release from the hydrogels were performed in phosphate buffered in saline (PBS, pH 7.4) at 37 °C for 12 days. The radiolabeling stability of the hydrogels was evaluated using ITLC under different experimental condition (human serum, normal saline, and PBS) at 37 °C for 12 days. Formatting the alginate-crosslinked layer on the CSH surface did not change the spherical morphology and the mean diameter (150 ± 10 μm). FT-IR spectra and zeta potential values indicate that alginate layer was formed successfully on the surface of the DI-CSH. In in vitro Dox release studies, the total percentage of the released Dox from the DI-CSH for 12 days were 60.9 ± 0.8, 67.3 ± 1.4, and 71.8 ± 2.5 % for 0.25, 0.50, and 1.00 mg Dox used to load into the hydrogels, respectively. On the other hand, after formatting alginate layer, the percentage of the

  10. Genetic Improvement of Root Growth Contributes to Efficient Phosphorus Acquisition in maize (Zea mays L.)

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yi-kai; CHEN Fan-jun; CHEN Xiao-chao; LONG Li-zhi; GAO Kun; YUAN Li-xing; ZHANG Fu-suo; MI Guo-hua

    2013-01-01

    Maize plants adapt to low phosphorus (P) stress by increasing root growth. It is of importance to know the extent to which genetic improvement of root growth can enhance P acquisiton. In the present study, the contribution of root growth improvement to efficient P acquisition was evaluated in two soils using T149 and T222, a pair of near isogenic maize testcrosses which were derived from a backcross BC4F3 population. T149 and T222 showed no difference in shoot biomass and leaf area under normal growth conditions, but differed greatly in root growth. T149 had longer lateral roots and a larger root surface area compared to T222. In calcareous soil, when P was insufficient, i.e., when P was either supplied as KH2PO4 at a concentration of 50 mg P kg-1 soil, or in the form of Phy-P, Ca3-P or Ca10-P, a 43%increase in root length in T149 compared to T222 resulted in an increase in P uptake by 53%, and shoot biomass by 48%. In acid soil, however, when P supply was insufficient, i.e., when P was supplied as KH2PO4 at a concentration of 100 mg P kg-1 soil, or in the form of Phy-P, Fe-P or Al-P, a 32%increase in root length in T149 compared to T222 resulted in an increase in P uptake by only 12%, and shoot biomass by 7%. No significant differences in the exudation of organic acids and APase activity were found between the two genotypes. It is concluded that genetic improvement of root growth can efficiently increase P acquisition in calcareous soils. In acid soils, however, improvements in the physiological traits of roots, in addition to their size, seem to be required for efficient P acquisition.

  11. Seed priming with chitosan improves the germination and growth performance of ajowan

    OpenAIRE

    Batool Mahdavi; Asghar Rahimi

    2013-01-01

    Background: Chitosan is a polysaccharide biopolymer derived from chitin. It not only stimulates growth and increases the crop yields but also alleviates the harmful effect of abiotic stress on plant growth. The objective of this study was to investigate the effects of chitosan on germination and growth of ajowan (Carum copticum) under salt stress. This study was conducted in a laboratory and greenhouse. Material and Methods: In the first experiment seed germination of ajowan monitored und...

  12. Largely improved tensile properties of chitosan film via unique synergistic reinforcing effect of carbon nanotube and clay.

    Science.gov (United States)

    Tang, Changyu; Xiang, Lixue; Su, Juanxia; Wang, Ke; Yang, Changyue; Zhang, Qin; Fu, Qiang

    2008-04-01

    In this work, a great synergistic effect of 2D clay platelets and 1D carbon nanotubes (CNTs) on reinforcing chitosan matrix has been observed for the first time. With incorporation of 3 wt % clay and 0.4 wt % CNTs, the tensile strength and Young's modulus of the nanocomposites are significantly improved by about 171 and 124%, respectively, compared with neat chitosan. This could be understood as due to the formation of much jammed fillers network with 1D CNTs and 2D clay platelets combined together, as indicated by rheological measurement. Our work demonstrates a good example for the preparation of high performance polymer nanocomposites by using nanofillers of different dimension together. PMID:18335921

  13. Cellulose acetate/hydroxyapatite/chitosan coatings for improved corrosion resistance and bioactivity

    Energy Technology Data Exchange (ETDEWEB)

    Zhong, Zhenyu; Qin, Jinli [Advanced Biomaterials and Tissue Engineering Center, Huazhong University of Science and Technology, Wuhan 430074 (China); Ma, Jun, E-mail: caltary@gmail.com [Advanced Biomaterials and Tissue Engineering Center, Huazhong University of Science and Technology, Wuhan 430074 (China); Department of Biomedical Engineering, School of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2015-04-01

    Cellulose acetate (CA) nanofibers were deposited on stainless steel plates by electrospinning technique. The composite of hydroxyapatite (HAP) nanoparticles and chitosan (CHI) was coated subsequently by dip-coating. The structure and morphology of the obtained coatings were investigated by Fourier transform infrared spectroscopy and scanning electron microscopy. The stability of the coatings in physiological environment was studied using electrochemical polarization and impedance spectroscopy. The CA nanofibers were embedded in the HAP/CHI coating and the resulted composite film was densely packed and uniform on the substrate. The in vitro biomineralization study of the coated samples immersed in simulated body fluid (SBF) confirmed the formation ability of bone-like apatite layer on the surface of HAP-containing coatings. Furthermore, the coatings could provide corrosion resistance to the stainless steel substrate in SBF. The electrochemical results suggested that the incorporation of CA nanofibers could improve the corrosion resistance of the HAP/CHI coating. Thus, biocompatible CA/HAP/CHI coated metallic implants could be very useful in the long-term stability of the biomedical applications. - Highlights: • The composite coatings were prepared by electrospinning and dip-coating. • Good in vitro bioactivity of the CA/HAP/CHI coating was confirmed. • Electrochemical behaviors in SBF of the coatings have been studied. • The CA/HAP/CHI coating shows better resistance property than HAP/CHI.

  14. Novel albendazole-chitosan nanoparticles for intestinal absorption enhancement and hepatic targeting improvement in rats.

    Science.gov (United States)

    Liu, Yang; Wang, Xiao-qing; Ren, Wei-xin; Chen, Yuan-lan; Yu, Yang; Zhang, Jian-kang; Bawudong, Dilimulati; Gu, Jun-peng; Xu, Xiao-dong; Zhang, Xue-nong

    2013-08-01

    To improve the treatment of helminthiasis, filariasis, and colorectal cancer, albendazole-associated chitosan nanoparticles (ABZ-CS-NPs) were prepared using the emulsion crosslinking volatile technique with contained sodium tripolyphosphate as the crosslinking agent and Poloxamer 188 as the auxiliary solvent. The structural characteristics of the NPs were determined using X-ray diffraction to analyze the interaction between CS and the drug. The NPs were then evaluated in terms of their physicochemical characteristics, drug release behavior, in vivo pharmacokinetic parameters, and biodistribution in animal studies. ABZ-loaded NPs with a uniformly spherical particle sizes (157.8 ± 2.82 nm) showed efficient drug loading, encapsulated efficiency, and high physical stability. The drug release from ABZ-CS-NPs was extended over several periods. Kinetic models were then fitted to determine the release mechanisms. ABZ and its metabolite albendazole sulfoxide (ABZSX) were analyzed in rats with mebendazole as the internal standard using reversed-phase high-performance liquid chromatography. Compared with the ABZ suspension groups, the relative bioavailability values of ABZ and ABZSX were 146.05 and 222.15%, respectively. In addition, the plasma concentration versus time curve is consistent with that of the two compartment models in the plasma concentration versus time curve. The results indicate that the ABZ-loaded NPs are promising novel ABZ candidates for passive diffusion in the treatment of hydatid cysts in the liver via oral administration. PMID:23529958

  15. Soil organic carbon dynamics of improved fallow-maize rotation systems under conventional and no-tillage in Central Zimbabwe

    NARCIS (Netherlands)

    Nyamadzawo, G.; Chikowo, R.; Nyamugafata, P.; Nyamangara, J.; Giller, K.E.

    2008-01-01

    Fallowing increases soil organic carbon (SOC) during the fallowing phase. However, this benefit is lost quickly during the cropping phase. The objective of this study was to evaluate SOC dynamics of an improved fallow-maize rotation under no-tillage (NT) and conventional tillage (CT) from time of fa

  16. Potassium Management for Improving Growth and Grain Yield of Maize (Zea mays L.) under Moisture Stress Condition

    Science.gov (United States)

    Amanullah; Iqbal, Asif; Irfanullah; Hidayat, Zeeshan

    2016-01-01

    Potassium (K) fertilizer management is beneficial for improving growth, yield and yield components of field crops under moisture stress condition in semiarid climates. Field experiments were conducted to study the response of maize (Zea mays L., cv. Azam) to foliar and soil applied K during summer 2013 and 2014. The experiments were carried out at the Agronomy Research Farm of The University of Agriculture Peshawar, Northwest Pakistan under limited irrigation (moisture stress) condition. It was concluded from the results that application of foliar K at the rate of 1–3% and foliar Zn at the rate of 0.1–0.2% was more beneficial in terms of better growth, higher yield and yield components of maize under moisture stress condition. Early spray (vegetative stage) resulted in better growth and higher yield than late spray (reproductive stage). Soil K treated plots (rest) plots performed better than control (K not applied) in terms of improved growth, higher yield and yield components of maize crop. The results further demonstrated that increasing the rate of soil applied K up to 90 kg P ha−1 in two equal splits (50% each at sowing and knee height) improve growth and maize productivity under semiarid climates. PMID:27694964

  17. Improved Biodegradable Radiation Cured Polymeric Film Prepared from Chitosan-Gelatin Blend

    Directory of Open Access Journals (Sweden)

    Zinia Nasreen

    2016-01-01

    Full Text Available The mechanical, thermal, swelling, and release properties of chitosan-gelatin (CG films have been investigated in order to verify the influence of UV and gamma radiation on the stability of the films. Thin films of chitosan and gelatin (1 : 3, w/w that were radiated with 100 krad of gamma dose showed the best performance and the TS values reached 25, 45, and 49 MPa, respectively, for chitosan, gelatin, and blend. The corresponding highest TS values were 23, 42, and 45 MPa, respectively, for 10 passes of UV radiation. The effect of radiation over gelatin, chitosan, and CG blend caused modification in the arrangement of molecules in the crystal lattice that is significant by XRD analysis. Surfaces of the films were also investigated by scanning electron microscope (SEM. Fourier transform infrared spectroscopy (FTIR studies further revealed structural changes of the films. These changes were attributed to understanding the behavior of the irradiated chitosan, gelatin, and CG blend on application of thermal energy using DSC and TGA studies, water uptake of the films in aqueous medium, and soil degradation properties to observe the best possibility for its application.

  18. Alfalfa (Medicago sativa L./maize (Zea mays L. intercropping provides a feasible way to improve yield and economic incomes in farming and pastoral areas of northeast China.

    Directory of Open Access Journals (Sweden)

    Baoru Sun

    Full Text Available Given the growing challenges to food and eco-environmental security as well as sustainable development of animal husbandry in the farming and pastoral areas of northeast China, it is crucial to identify advantageous intercropping modes and some constraints limiting its popularization. In order to assess the performance of various intercropping modes of maize and alfalfa, a field experiment was conducted in a completely randomized block design with five treatments: maize monoculture in even rows, maize monoculture in alternating wide and narrow rows, alfalfa monoculture, maize intercropped with one row of alfalfa in wide rows and maize intercropped with two rows of alfalfa in wide rows. Results demonstrate that maize monoculture in alternating wide and narrow rows performed best for light transmission, grain yield and output value, compared to in even rows. When intercropped, maize intercropped with one row of alfalfa in wide rows was identified as the optimal strategy and the largely complementary ecological niches of alfalfa and maize were shown to account for the intercropping advantages, optimizing resource utilization and improving yield and economic incomes. These findings suggest that alfalfa/maize intercropping has obvious advantages over monoculture and is applicable to the farming and pastoral areas of northeast China.

  19. Much Improved Irrigation Use Efficiency in an Intensive Wheat-Maize Double Cropping System in the North China Plain

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Crop yield and water use efficiency (WUE) in a wheat-maize double cropping system are influenced by short and uneven rainfalls in the North China Plain (NCP). A 2-year experiment was conducted to investigate the effects of irrigation on soil water balance, crop yield and WUE to improve irrigation use efficiency in the cropping system. Soil water depletion (△SWS)by crop generally decreased with the increase of irrigation and rainfall, while △SWS for the whole rotation was relatively stable among these irrigation treatments. High irrigations in wheat season increased initial soil moisture and △SWS for subsequent maize especially in the drought season. Initial soil water influenced mainly by the irrigation and rainfall in the previous crop season, is essential to high yield in such cropping systems. Grain yield decreased prior to evapotranspiration(ET) when ET reached about 300 mm for wheat, while maize showed various WUEs with similar seasonal ET. For whole rotation, WUE declined when ET exceeded about 650 mm. These results indicate great potential for improving irrigation use efficiency in such wheat-maize cropping system in the NCP. Based on the present results, reasonable irrigation schedules according to different annual rainfall conditions are presented for such a cropping system.

  20. Production and characterization of chitosan/gelatin/β-TCP scaffolds for improved bone tissue regeneration

    Energy Technology Data Exchange (ETDEWEB)

    Serra, I.R.; Fradique, R.; Vallejo, M.C.S.; Correia, T.R.; Miguel, S.P.; Correia, I.J., E-mail: icorreia@ubi.pt

    2015-10-01

    Recently, bone tissue engineering emerged as a viable therapeutic alternative, comprising bone implants and new personalized scaffolds to be used in bone replacement and regeneration. In this study, biocompatible scaffolds were produced by freeze-drying, using different formulations (chitosan, chitosan/gelatin, chitosan/β-TCP and chitosan/gelatin/β-TCP) to be used as temporary templates during bone tissue regeneration. Sample characterization was performed through attenuated total reflectance-Fourier transform infrared spectroscopy, X-ray diffraction and energy dispersive spectroscopy analysis. Mechanical characterization and porosity analysis were performed through uniaxial compression test and liquid displacement method, respectively. In vitro studies were also done to evaluate the biomineralization activity and the cytotoxic profile of the scaffolds. Scanning electron and confocal microscopy analysis were used to study cell adhesion and proliferation at the scaffold surface and within their structure. Moreover, the antibacterial activity of the scaffolds was also evaluated through the agar diffusion method. Overall, the results obtained revealed that the produced scaffolds are bioactive and biocompatible, allow cell internalization and show antimicrobial activity against Staphylococcus aureus. Such, make these 3D structures as potential candidates for being used on the bone tissue regeneration, since they promote cell adhesion and proliferation and also prevent biofilm development at their surfaces, which is usually the main cause of implant failure. - Highlights: • Production of 3D scaffolds composed by chitosan/gelatin/β-TCP by freeze-drying for bone regeneration • Physicochemical characterization of the bone substitutes by SEM, FTIR, XRD and EDS • Evaluation of the cytotoxic profile and antibacterial activity of the 3D structures through in vitro assays.

  1. Nitrogen Deifciency Limited the Improvement of Photosynthesis in Maize by Elevated CO2 Under Drought

    Institute of Scientific and Technical Information of China (English)

    ZONG Yu-zheng; SHANGGUAN Zhou-ping

    2014-01-01

    Global environmental change affects plant physiological and ecosystem processes. The interaction of elevated CO2, drought and nitrogen (N) deficiency result in complex responses of C4 species photosynthetic process that challenge our current understanding. An experiment of maize (Zea mays L.) involving CO2 concentrations (380 or 750 µmol mol-1, climate chamber), osmotic stresses (10% PEG-6000, -0.32 MPa) and nitrogen constraints (N deficiency treated since the 144th drought hour) was carried out to investigate its photosynthesis capacity and leaf nitrogen use efficiency. Elevated CO2 could alleviate drought-induced photosynthetic limitation through increasing capacity of PEPC carboxylation (Vpmax) and decreasing stomatal limitations (SL). The N deifciency exacerbated drought-induced photosynthesis limitations in ambient CO2. Elevated CO2 partially alleviated the limitation induced by drought and N deifciency through improving the capacity of Rubisco carboxylation (Vmax) and decreasing SL. Plants with N deifciency transported more N to their leaves at elevated CO2, leading to a high photosynthetic nitrogen-use efifciency but low whole-plant nitrogen-use efifciency. The stress mitigation by elevated CO2 under N deifciency conditions was not enough to improving plant N use efifciency and biomass accumulation. The study demonstrated that elevated CO2 could alleviate drought-induced photosynthesis limitation, but the alleviation varied with N supplies.

  2. Comparative effectiveness of different Rhizobium sp. for improving growth and yield of maize (Zea mays L.

    Directory of Open Access Journals (Sweden)

    Ijaz Mehboob, Zahir Ahmad Zahir, Muhammad Arshad, Muhammad Khalid

    2012-05-01

    Full Text Available During the last couple of decades, it has been demonstrated that rhizobia can associate with roots of non-legumes also without forming true nodules, and can promote their growth by using one or more of the direct or indirect mechanisms of actions. This work examines the growth and yield responses of maize to inoculation with different species of rhizobia, isolated from the root nodules of chickpea (Cicer arietinum L., lentil (Lens culinaris M. and mung bean (Vigna radiata L. in pots and fields. Twenty isolates of rhizobia were isolated from root nodules each of mung bean, lentil and chickpea and were screened under axenic conditions. On the basis of their promising performance under axenic conditions, nine most efficient isolates (three from each legume host were selected, characterized and further evaluated for their growth promoting activities by conducting pot and field experiments. Results of pot experiment revealed that maximum increase in grain yield, 1000 grain weight, N, P and K uptake (up to 47.89, 54.52, 73.46, 84.66 and 59.19% by CRI28, respectively, over un-inoculated control was produced by the isolate of Mesorhizobium ciceri. Whereas, maximum improvement in rest of the parameters was caused by the isolates of Rhizobium phaseoli (i.e. fresh biomass, straw yield and root length up to 36.30% by A18, 25.46% by S6 and 81.89% by A18, respectively over un-inoculated control. Rhizobium leguminosarum isolates came out to be the least effective among the species tested. Similarly, all the selected isolates improved the growth and yield attributing parameters in fields as well but with varying capacity compared with un-inoculated control. The selected isolates of Mesorhizobium ciceri and Rhizobium phaseoli again remained superior compared to the isolates of Rhizobium leguminosarum under field conditions. The results of this study imply that rhizobium species had potential to promote growth and yield of maize but this technology should be

  3. Chitosan-based dressings loaded with neurotensin—an efficient strategy to improve early diabetic wound healing

    OpenAIRE

    Moura, Liane I. F.; Dias, Ana M. A.; Ermelindo C. Leal; Carvalho, Lina; Sousa, Hermínio C. de; Carvalho, Eugénia

    2014-01-01

    One important complication of diabetes mellitus is chronic, non-healing diabetic foot ulcers (DFUs). This study aims to develop and use dressings based on chitosan derivatives for the sustained delivery of neurotensin (NT), a neuropeptide that acts as an inflammatory modulator in wound healing. Three different derivatives, namely N-carboxymethyl chitosan, 5-methyl pyrrolidinone chitosan (MPC) and N-succinyl chitosan, are presented as potential biomaterials for wound healing applications. Our ...

  4. Nutritional and safety assessments of foods and feeds nutritionally improved through biotechnology: lysine maize as a case study.

    Science.gov (United States)

    Glenn, Kevin C

    2007-01-01

    During the last decade, the area of biotech crops modified for agronomic input traits (e.g., herbicide tolerance and insect protection) has increased to 90 million halyear, grown by over 8 million farmers in a total of 17 countries. As adoption of these improved agronomic trait biotech crops has grown, so has interest in biotech crops that have improved nutritional characteristics for use as feed and food. A previous publication by the International Life Sciences Institute (ILSI) reported on the principles and concepts proposed for the nutritional and safety assessments of foods and feeds nutritionally improved through biotechnology. In this paper, the guidelines and principles recommended in the earlier publication are discussed relative to a specific case study, Lysine maize. Lysine maize is a feed ingredient with enhanced nutritional characteristics for poultry and swine and provides an alternative to the need for addition of supplemental lysine to some diets for these animals. The 2004 Task Force of the ILSI has also applied the concepts from that report to 4 other case studies: sweet potato enriched in provitamin A (2 examples, one using biotechnology and one using conventional breeding); Golden Rice 2; double-embryo maize; and ASP-1 enhanced protein sweet potato. PMID:17955996

  5. Utilization of maize cob biochar and rice husk charcoal as soil amendments for improving acid soil fertility and productivity

    Directory of Open Access Journals (Sweden)

    Nurhidayati

    2014-10-01

    Full Text Available The decline in soil fertility in agricultural land is a major problem that causes a decrease in the production of food crops. One of the causes of the decline in soil fertility is declining soil pH that caused the decline in the availability of nutrients in the soil. This study aimed to assess the influence of alternative liming materials derived from maize cob biochar and rice husk charcoal compared to conventional lime to improve soil pH, soil nutrient availability and maize production. The experiment used a factorial complete randomized design which consisting of two factors. The first factor is the type of soil amendment which consists of three levels (calcite lime, rice husk charcoal and cob maize biochar. The second factor is the application rates of the soil amendment consisted of three levels (3, 6 and 9 t/ha and one control treatment (without soil amendment. The results of this study showed that the application of various soil amendment increased soil pH, which the pH increase of the lime application was relatively more stable over time compared to biochar and husk charcoal. The average of the soil pH increased for each soil amendment by 23% (lime, 20% (rice husk charcoal and 23% (biochar as compared with control. The increase in soil pH can increase the availability of soil N, P and K. The greatest influence of soil pH on nutrient availability was shown by the relationship between soil pH and K nutrient availability with R2 = 0.712, while for the N by R2 = 0.462 and for the P by R2 = 0.245. The relationship between the availability of N and maize yield showed a linear equation. While the relationship between the availability of P and K with the maize yield showed a quadratic equation. The highest maize yield was found in the application of biochar and rice husk charcoal with a dose of 6-9 t/ha. The results of this study suggested that biochar and husk charcoal could be used as an alternative liming material in improving acid soil

  6. Nanoamphiphilic Chitosan Dispersed Poly(lactic acid) Bionanocomposite Films with Improved Thermal, Mechanical, and Gas Barrier Properties.

    Science.gov (United States)

    Pal, Akhilesh Kumar; Katiyar, Vimal

    2016-08-01

    This article demonstrates the synthesis of lactic acid oligomer-grafted-chitosan (OLLA-g-CH), a nanoamphiphilic molecule, by in situ condensation polymerization and its effective use as a nanofiller for improvement in multiple properties of poly(lactic acid) (PLA) films, essential for stringent food packaging applications. Fourier transform infrared spectroscopy (FTIR) analysis shows the presence of amide-ester bond at 1539 cm(-1), which confirms the structural grafting of OLLA chains with chitosan molecules. This nanoamphiphilic OLLA-g-CH molecule act as surfactant containing hydrophilic chitosan head and hydrophobic OLLA tails with average size in the range of ∼2-4 nm. Prepared PLA/OLLA-g-CH bionanocomposite films appear with uniform dispersion of nanoamphiphilic OLLA-g-CH molecules with self-assembled micelles having size as low as ∼20 nm and as high as ∼150 nm with core-shell morphology in PLA matrix. This nanofiller is found very effective toward significant reduction in oxygen permeability (OP) by ∼10-fold due to the reduction in solubility of oxygen molecules and improvement in crystal nucleation density due to availability of nanonucleating sites. Ultimate tensile strength (UTS) of PLA/OLLA-g-CH bionanocomposite films are relatively comparable to that of PLA, however, elongation at break is improved significantly. The onset of thermal degradation of PLA/(OLLA-g-CH) films is also found comparable to that of PLA film. The glass transition temperature (Tg) of bionanocomposites is decreased by more than 18 °C with increase in OLLA-g-CH loading, which indicates the improved plasticization characteristics of PLA matrix. The crystallization kinetics suggest nonthree dimensional truncated spherical structures, which is controlled by the combination of thermal and athermal instantaneous nucleations. POM analysis suggested that the spherulite growth of PLA is improved significantly with the addition of OLLA-g-CH. The reduction in Tg of PLA with improvement

  7. Halofuginone- and Chitosan-Coated Amnion Membranes Demonstrate Improved Abdominal Adhesion Prevention

    Directory of Open Access Journals (Sweden)

    Scott Washburn

    2010-01-01

    Full Text Available Our objective was to determine whether coating the amniotic membrane with halofuginone, a type 1 collagen synthase inhibitor, with or without the hemostasis-inducing substance chitosan, reduced the number and severity of adhesions in the rat uterine horn injury model. Sixty retired breeder Sprague-Dawley rats underwent midline laparotomy and a zone of ischemia was created in the left uterine horn of each animal. Rats were randomized to one of six treatment groups: (1 untreated control, (2 oxidized regenerated cellulose (Interceed® (ORC, (3 plain amnion, (4 amnion coated on both sides with 0.5% solution of halofuginone (HAH, (5 amnion coated on one side with 0.5% halofuginone and on the other side with chitosan (CAH, or (6 amnion coated on both sides with chitosan (CAC. The zone of ischemia in each left uterine horn was wrapped in each treatment. Rats were sacrificed 2 weeks after laparotomy, and adhesions were counted and scored for severity. Data were analyzed using Chi square and a p <0.05 was considered significant. Our results showed that there were no differences in the percentage of animals with adhesions in the untreated, ORC, plain amnion, or CAC groups. No adhesions formed in any animal in the HAH group and only 14% of the animals developed adhesions to the uterine horn in the CAH group (p < 0.05. The percentage of animals with moderate and severe adhesions did not differ between untreated controls and the ORC groups, but were significantly reduced in all four of the amnion groups: plain amnion, HAH, CAH, and CAC (p < 0.05. Amnion coated with halofuginone alone or in combination with chitosan reduced the percentage of animals with adhesions, as well as the percentage of animals with moderate and severe adhesions compared to untreated controls and the ORC group in the rat uterine horn injury model. Amnion alone or coated with chitosan reduced the percentage of rats with moderate and severe adhesions, but not the percentage of rats with

  8. Trehalose accumulation in Azospirillum brasilense improves drought tolerance and biomass in maize plants.

    Science.gov (United States)

    Rodríguez-Salazar, Julieta; Suárez, Ramón; Caballero-Mellado, Jesús; Iturriaga, Gabriel

    2009-07-01

    Bacteria of the genus Azospirillum increase the grain yield of several grass crops. In this work the effect of inoculating maize plants with genetically engineered Azospirillum brasilense for trehalose biosynthesis was determined. Transformed bacteria with a plasmid harboring a trehalose biosynthesis gene-fusion from Saccharomyces cerevisiae were able to grow up to 0.5 M NaCl and to accumulate trehalose, whereas wild-type A. brasilense did not tolerate osmotic stress or accumulate significant levels of the disaccharide. Moreover, 85% of maize plants inoculated with transformed A. brasilense survived drought stress, in contrast with only 55% of plants inoculated with the wild-type strain. A 73% increase in biomass of maize plants inoculated with transformed A. brasilense compared with inoculation with the wild-type strain was found. In addition, there was a significant increase of leaf and root length in maize plants inoculated with transformed A. brasilense. Therefore, inoculation of maize plants with A. brasilense containing higher levels of trehalose confers drought tolerance and a significant increase in leaf and root biomass. This work opens the possibility that A. brasilense modified with a chimeric trehalose biosynthetic gene from yeast could increase the biomass, grain yield and stress tolerance in other relevant crops.

  9. Research Status on Drought Performance Improvement of Maize%提高玉米耐旱、抗旱性能的研究现状

    Institute of Scientific and Technical Information of China (English)

    梁鸡保; 龚靖世; 李志军; 李琛

    2012-01-01

    As one of major food crops in China, maize production is extremely affected by drought. Improve the drought resistance and tolerance of maize is imperative. The effect of drought stress on maize yield at different growth periods was in-trodused. And the research progress on drought performance improvement of maize was summarized.%作为中国主要的粮食作物之一,玉米产量受干旱影响极其严重,提高玉米的耐旱、抗旱性能势在必行.在介绍干旱胁迫在不同时期对玉米产量影响的基础上,综述了目前在玉米耐旱、抗旱性能提高方面的研究现状,并进行了展望.

  10. Improving the stability of chitosan-gelatin-based hydrogels for cell delivery using transglutaminase and controlled release of doxycycline.

    Science.gov (United States)

    Tormos, Christian J; Abraham, Carol; Madihally, Sundararajan V

    2015-12-01

    Although local cell delivery is an option to repair tissues, particularly using chitosan-based hydrogels, significant attrition of injected cells prior to engraftment has been a problem. To address this problem, we explored the possibility of stabilizing the chitosan-gelatin (CG) injectable hydrogels using (1) controlled release of doxycycline (DOX) to prevent premature degradation due to increased gelatinase activity (MMP-2 and MMP-9), and (2) transglutaminase (TG) to in situ cross-link gelatin to improve the mechanical stability. We prepared DOX-loaded PLGA nanoparticles, loaded into the CG hydrogels, measured DOX release for 5 days, and modeled using a single-compartmental assumption. Next, we assessed the influence of TG and DOX on hydrogel compression properties by incubating hydrogels for 7 days in PBS. We evaluated the effect of these changes on retention of fibroblasts and alterations in MMP-2/MMP-9 activity by seeding 500,000 fibroblasts for 5 days. These results showed that 90 % of DOX released from cross-linked CG hydrogels after 4 days, unlike CG hydrogels where 90 % of DOX was released within the first day. Addition of TG enhanced the CG hydrogel stability significantly. More than 60 % of seeded fibroblasts were recovered from the CG-TG hydrogels at day 5, unlike 40 % recovered from CG-hydrogels. Inhibition of MMP-2/MMP-9 were observed. In summary, controlled release of DOX from CG hydrogels cross-linked with TG shows a significant potential as a carrier for cell delivery.

  11. Identification and genetic characterization of maize cell wall variation for improved biorefinery feedstock characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Pauly, Markus [UC Berkeley; Hake, Sarah [USDA Albany

    2013-10-31

    The objectives of this program are to 1) characterize novel maize mutants with altered cell walls for enhanced biorefinery characteristics and 2) find quantitative trait loci (QTLs) related to biorefinery characteristics by taking advantage of the genetic diversity of maize. As a result a novel non-transgenic maize plant (cal1) has been identified, whose stover (leaves and stalk) contain more glucan in their walls leading to a higher saccharification yield, when subjected to a standard enzymatic digestion cocktail. Stacking this trait with altered lignin mutants yielded evene higher saccharification yields. Cal-1 mutants do not show a loss of kernel and or biomass yield when grown in the field . Hence, cal1 biomass provides an excellent feedstock for the biofuel industry.

  12. Superparamagnetic iron oxide/chitosan core/shells for hyperthermia application: Improved colloidal stability and biocompatibility

    Energy Technology Data Exchange (ETDEWEB)

    Patil, R.M.; Shete, P.B.; Thorat, N.D.; Otari, S.V. [Center for Interdisciplinary Research, D.Y. Patil University, Kolhapur 416006, MS (India); Barick, K.C.; Prasad, A.; Ningthoujam, R.S. [Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085, MS (India); Tiwale, B.M. [Center for Interdisciplinary Research, D.Y. Patil University, Kolhapur 416006, MS (India); Pawar, S.H., E-mail: pawar_s_h@yahoo.com [Center for Interdisciplinary Research, D.Y. Patil University, Kolhapur 416006, MS (India)

    2014-04-15

    Superparamagnetic magnetite nanoparticles are of great interest due to their potential biomedical applications. In the present investigation, Fe{sub 3}O{sub 4} magnetic nanoparticles were prepared by alkaline precipitation using ferrous chloride as the sole source. An amphiphilic polyelectrolyte with the property of biocompatibility and functional carboxyl groups was used as a stabilizer to prepare a well-dispersed suspension of superparamagnetic Fe{sub 3}O{sub 4} nanoparticles. The final material composed of Fe{sub 3}O{sub 4} core and chitosan (CH) shell was produced. The amino groups of CH coated on Fe{sub 3}O{sub 4} nanoparticles were further cross linked using glutaraldehyde (GLD) for stable coating. FTIR spectra, XPS and TGA confirmed the coating of CH/GLD on the surface of Fe{sub 3}O{sub 4} nanoparticles. XRD patterns indicate the pure phase Fe{sub 3}O{sub 4} with a spinel structure. The nanoparticles were superparamagnetic at room temperature with saturation magnetization values for bare and coated nanoparticles which were 51.68 emu/g and 48.60 emu/g, respectively. Zeta potential values showed higher colloidal stability of coated nanoparticles than the bare one. Cytotoxicity study up to 2 mg mL{sup −1} concentration showed no drastic change in cell viability of nanoparticles after coating. Also, coated nanoparticles showed increased SAR value, making them suitable for hyperthermia therapy application. - Highlights: • Fe{sub 3}O{sub 4} nanoparticles were synthesized from FeCl{sub 2} as the sole source by alkaline precipitation. • Coating of Fe{sub 3}O{sub 4} nanoparticles was done with chitosan by simple ultrasonication. • Chitosan cross-linked with glutaraldehyde. • High colloidal stability was observed. • Increased SAR value and least cytotoxicity were observed.

  13. A maize phytochrome-interacting factor 3 improves drought and salt stress tolerance in rice.

    Science.gov (United States)

    Gao, Yong; Jiang, Wei; Dai, Yi; Xiao, Ning; Zhang, Changquan; Li, Hua; Lu, Yi; Wu, Meiqin; Tao, Xiaoyi; Deng, Dexiang; Chen, Jianmin

    2015-03-01

    Phytochrome-interacting factor 3 (PIF3) activates light-responsive transcriptional network genes in coordination with the circadian clock and plant hormones to modulate plant growth and development. However, little is known of the roles PIF3 plays in the responses to abiotic stresses. In this study, the cloning and functional characterization of the ZmPIF3 gene encoding a maize PIF3 protein is reported. Subcellular localization revealed the presence of ZmPIF3 in the cell nucleus. Expression patterns revealed that ZmPIF3 is expressed strongly in leaves. This expression responds to polyethylene glycol, NaCl stress, and abscisic acid application, but not to cold stress. ZmPIF3 under the control of the ubiquitin promoter was introduced into rice. No difference in growth and development between ZmPIF3 transgenic and wild-type plants was observed under normal growth conditions. However, ZmPIF3 transgenic plants were more tolerant to dehydration and salt stresses. ZmPIF3 transgenic plants had increased relative water content, chlorophyll content, and chlorophyll fluorescence, as well as significantly enhanced cell membrane stability under stress conditions. The over-expression of ZmPIF3 increased the expression of stress-responsive genes, such as Rab16D, DREB2A, OSE2, PP2C, Rab21, BZ8 and P5CS, as detected by real-time PCR analysis. Taken together, these results improve our understanding of the role ZmPIF3 plays in abiotic stresses signaling pathways; our findings also indicate that ZmPIF3 regulates the plant response to drought and salt stresses. PMID:25636202

  14. Development and characterization of an edible composite film based on chitosan and virgin coconut oil with improved moisture sorption properties.

    Science.gov (United States)

    Binsi, P K; Ravishankar, C N; Srinivasa Gopal, T K

    2013-04-01

    An edible composite film was prepared from an emulsion system based on chitosan and virgin coconut oil (VCO). The effect of incorporation of VCO was evaluated at various concentrations and the optimum concentration was chosen based on resultant changes in the properties of the film. Addition of VCO in film forming solution resulted in increase in film thickness and marginal reduction in film transparency. Compatibility of VCO with chitosan was better at lower concentration of VCO as indicated by the microstructure of composite film in scanning electron micrographs. Phase separation was evident at higher level of oil incorporation and the optimal oil/chitosan ratio was determined to be at 0.5 to 1 mL/g chitosan. Furthermore, chemical interaction took place between VCO and chitosan as revealed by Fourier transform infrared spectroscopy data. Even though control chitosan films exhibited superior gas barrier properties, composite film with optimum VCO concentration revealed better mechanical and moisture sorption properties.

  15. Enhancing Biological Wastewater Treatment with Chitosan

    Institute of Scientific and Technical Information of China (English)

    陈亮; 陈东辉; 朱珺

    2003-01-01

    Chitin and chitosan have been applied to biological wastewater treatment.From a number of parallel comparison experiments,it can be concluded that the application of chitin and chitosan can both enhance the biological treatment,besides which chitosan is more efficient than chitin.The study on the enhancement mechanism reveals the difference between the two additives:chitosan improves the sludge structure and settlibility,while chitin acts as a kind of carrier for microorganism in the biological treatment system.

  16. Towards improved nitrogen management in silage maize production on sandy soils.

    NARCIS (Netherlands)

    Schroder, J.J.

    1998-01-01

    Maize has become a highly appreciated crop in Dutch dairy farming during the last 25 years. The current cropping technique, however, is associated with a low recovery of soil mineral nitrogen (N) and serious losses of N to the environment. This gave rise to the research described in this thesis whic

  17. Improving weed management and crop productivity in maize systems in Zimbabwe

    NARCIS (Netherlands)

    Mashingaidze, A.B.

    2004-01-01

    Keywords: Intercropping, narrow planting, precise fertilizer placement, radiation interception, leaf stripping, detasselling, Land Equivalent Ratio, maize, pumpkin, dry beans, reduced herbicide dosagesIn the tropics, weeds cause more

  18. Evaluation of Chitosan-Starch-Based Edible Coating To Improve the Shelf Life of Bod Ljong Cheese.

    Science.gov (United States)

    Mei, Jun; Guo, Qizhen; Wu, Yan; Li, Yunfei

    2015-07-01

    The objective of this work was to evaluate the effectiveness of antimicrobial edible coatings to improve the quality of Bod ljong cheese throughout 25 days of storage. Coatings were prepared using chitosan, water chestnut starch, and glycerol as a base matrix, together with several combinations of antimicrobial substances: Cornus officinalis fruit extract (COFE), pine needle essential oil (PNEO), and nisin. Application of coating on cheese decreased water loss, lipid oxidation, changes in headspace gas composition, and color. Moreover, the edible coatings with COFE or PNEO had increased antimicrobial activity and did not permit growth of microorganisms. COFE and PNEO are manufactured from food-grade materials so they can be consumed as an integral part of the cheese, which represents a competitive advantage over nonedible coatings.

  19. Flavone-rich maize: An opportunity to improve the nutritional value of an important commodity crop

    Directory of Open Access Journals (Sweden)

    Maria Isabel Casas

    2014-09-01

    Full Text Available Agricultural outputs have resulted in food production continuously expanding. Satisfying the needs of a fast growing human population, higher yields, more efficient food processing, and food esthetic value, resulted in crop varieties with higher caloric intake but lacking many phytochemicals important for plant protection and adequate human nutrition. The increasing incidence of chronic diseases such as obesity, diabetes and cardiovascular diseases, combined with social disparity worldwide prompted the interest in developing enhanced crops that can simultaneously address the two sides of the current malnutrition sword, increasing yield while providing added nutritional value. Flavones, phytochemicals associated with the beneficial effects of the Mediterranean diet, have potent anti-inflammatory and anti-carcinogenic activities. However, many Mediterranean diet-associated vegetables are inaccessible, or lowly consumed, in many parts of the world. Maize is the most widely grown cereal crop, yet most lines used for hybrid maize production lack flavones. As a first step towards a sustainable strategy to increasing the nutritional value of maize-based diets, we investigated the accumulation and chemical properties of flavones in maize seeds of defined genotypes. We show that the pericarps of the P1-rr genotype accumulate flavones at levels comparable to those present in some flavone-rich vegetables, and are mostly present in their C- and O-glycosylated forms. Some of these glycosides can be readily converted into the corresponding more active health beneficial aglycones during food processing. Our results provide evidence that nutritionally beneficial flavones could be re-introduced into elite lines to increase the dietary benefits of maize.

  20. Improving stability and biocompatibility of alginate/chitosan microcapsule by fabricating bi-functional membrane.

    Science.gov (United States)

    Zheng, Guoshuang; Liu, Xiudong; Wang, Xiuli; Chen, Li; Xie, Hongguo; Wang, Feng; Zheng, Huizhen; Yu, Weiting; Ma, Xiaojun

    2014-05-01

    Cell encapsulation technology holds promise for the cell-based therapy. But poor mechanical strength and biocompatibility of microcapsule membrane are still obstacles for the clinical applications. A novel strategy is presented to prepare AC₁ C₂ A microcapsules with bi-functional membrane (that is, both desirable biocompatibility and membrane stability) by sequentially complexing chitosans with higher deacetylation degree (C₁) and lower deacetylation degree (C₂) on alginate (A) gel beads. Both in vitro and in vivo evaluation of AC₁C₂ A microcapsules demonstrate higher membrane stability and less cell adhesion, because the introduction of C₂ increases membrane strength and decreases surface roughness. Moreover, diffusion test of AC₁C₂ A microcapsules displays no inward permeation of IgG protein suggesting good immunoisolation function. The results demonstrate that AC₁C₂ A microcapsules with bi-functional membrane could be a promising candidate for microencapsulated cell implantation with cost effective usage of naturally biocompatible polysaccharides.

  1. Characterization of Chitosan Nanofiber Sheets for Antifungal Application

    Directory of Open Access Journals (Sweden)

    Mayumi Egusa

    2015-11-01

    Full Text Available Chitosan produced by the deacetylation of chitin is a cationic polymer with antimicrobial properties. In this study, we demonstrate the improvement of chitosan properties by nanofibrillation. Nanofiber sheets were prepared from nanofibrillated chitosan under neutral conditions. The Young’s modulus and tensile strength of the chitosan NF sheets were higher than those of the chitosan sheets prepared from dissolving chitosan in acetic acid. The chitosan NF sheets showed strong mycelial growth inhibition against dermatophytes Microsporum and Trichophyton. Moreover, the chitosan NF sheets exhibited resistance to degradation by the fungi, suggesting potentials long-lasting usage. In addition, surface-deacetylated chitin nanofiber (SDCNF sheets were prepared. The SDCNF sheet had a high Young’s modulus and tensile strength and showed antifungal activity to dermatophytes. These data indicate that nanofibrillation improved the properties of chitosan. Thus, chitosan NF and SDCNF sheets are useful candidates for antimicrobial materials.

  2. Development by extrusion of soyabari snack sticks: a nutritionally improved soya-maize product based on the Nigerian snack (kokoro).

    Science.gov (United States)

    Omueti, O; Morton, I D

    1996-01-01

    A nutritionally improved local snack compared to existing kokoro has been developed by extrusion cooking of different formulations of maize, soybean and condiments such as pepper, onion, salt, palm oil, plantain and banana. The improved snack was named as the 'soyabari snack stick'. The chemical composition of representative extruded products indicates a high level of crude protein, fat, energy, available lysine and improved in vitro digestibility compared to the usual maize-based products. The level of stachyose and raffinose were greatly reduced in the extruded products compared to raw soya. Formulations using various additives yielded products suitable for different consumers' preferences such as hot, sweet, bland, gritty or crispy and acceptable to taste assessors. Soyabari snack sticks were equally acceptable as Bombay mix, a product on the market in London. Sensory analysis showed no significant differences in the two products but the crude fibre content of Bombay mix was higher while the protein was slightly lower than for soyabari sticks. Local ingredients can produce acceptable extrudates. PMID:8616673

  3. Conversion to No-Till Improves Maize Nitrogen Use Efficiency in a Continuous Cover Cropping System

    Science.gov (United States)

    Habbib, Hazzar; Verzeaux, Julien; Nivelle, Elodie; Roger, David; Lacoux, Jérôme; Catterou, Manuella; Hirel, Bertrand; Dubois, Frédéric; Tétu, Thierry

    2016-01-01

    A two-year experiment was conducted in the field to measure the combined impact of tilling and N fertilization on various agronomic traits related to nitrogen (N) use efficiency and to grain yield in maize cultivated in the presence of a cover crop. Four years after conversion to no-till, a significant increase in N use efficiency N harvest index, N remobilization and N remobilization efficiency was observed both under no and high N fertilization conditions. Moreover, we observed that grain yield and grain N content were higher under no-till conditions only when N fertilizers were applied. Thus, agronomic practices based on continuous no-till appear to be a promising for increasing N use efficiency in maize. PMID:27711154

  4. Strategies to improve low copy transgenic events in Agrobacterium-mediated transformation of maize.

    Science.gov (United States)

    Sivamani, Elumalai; Li, Xianggan; Nalapalli, Samson; Barron, Yoshimi; Prairie, Anna; Bradley, David; Doyle, Michele; Que, Qiudeng

    2015-12-01

    Transgenic plants containing low copy transgene insertion free of vector backbone are highly desired for many biotechnological applications. We have investigated two different strategies for increasing the percentage of low copy events in Agrobacterium-mediated transformation experiments in maize. One of the strategies is to use a binary vector with two separate T-DNAs, one T-DNA containing an intact E.coli manA gene encoding phosphomannose isomerase (PMI) as selectable marker gene cassette and another T-DNA containing an RNAi cassette of PMI sequences. By using this strategy, low copy transgenic events containing the transgenes were increased from 43 to 60 % in maize. An alternate strategy is using selectable marker gene cassettes containing regulatory or coding sequences derived from essential plant genes such as 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) or MADS box transcription factor. In this paper we demonstrate that higher percentage of low copy transgenic events can be obtained in Agrobacterium-mediated maize transformation experiments using both strategies. We propose that the above two strategies can be used independently or in combination to increase transgenic events that contain low copy transgene insertion in Agrobacterium-mediated transformation experiments. PMID:26338266

  5. Strategies to improve low copy transgenic events in Agrobacterium-mediated transformation of maize.

    Science.gov (United States)

    Sivamani, Elumalai; Li, Xianggan; Nalapalli, Samson; Barron, Yoshimi; Prairie, Anna; Bradley, David; Doyle, Michele; Que, Qiudeng

    2015-12-01

    Transgenic plants containing low copy transgene insertion free of vector backbone are highly desired for many biotechnological applications. We have investigated two different strategies for increasing the percentage of low copy events in Agrobacterium-mediated transformation experiments in maize. One of the strategies is to use a binary vector with two separate T-DNAs, one T-DNA containing an intact E.coli manA gene encoding phosphomannose isomerase (PMI) as selectable marker gene cassette and another T-DNA containing an RNAi cassette of PMI sequences. By using this strategy, low copy transgenic events containing the transgenes were increased from 43 to 60 % in maize. An alternate strategy is using selectable marker gene cassettes containing regulatory or coding sequences derived from essential plant genes such as 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) or MADS box transcription factor. In this paper we demonstrate that higher percentage of low copy transgenic events can be obtained in Agrobacterium-mediated maize transformation experiments using both strategies. We propose that the above two strategies can be used independently or in combination to increase transgenic events that contain low copy transgene insertion in Agrobacterium-mediated transformation experiments.

  6. Modiifed fertilization management of summer maize (Zea mays L.) in northern China improves grain yield and efifciency of nitrogen use

    Institute of Scientific and Technical Information of China (English)

    CHENG Yi; ZHAO Jie; LIU Zhen-xiang; HUO Zhi-jin; LIU Peng; DONG Shu-ting; ZHANG Ji-wang; ZHAO Bin

    2015-01-01

    Improving the yield of maize grain per unit area is needed to meet the growing demand for it in China, where the availability of fertile land is very limited. Modiifed fertilization management and planting density are efifcient methods for increasing crop yield. Field experiments were designed to investigate the inlfuence of modiifed fertilization management and planting density on grain yield and nitrogen use efifciency of the popular maize variety Zhengdan 958, in four treatments including local farmer’s practice (FP), high-yielding and high efifciency cultivation (HH), super high-yielding cultivation (SH), and the control (CK). Trials were conducted in three locations of the Huang-Huai-Hai Plain in northern China. Compared with FP, SH was clearly able to promote N absorption and dry matter accumulation in post-anthesis, and achieve high yield and N use efifciency by increasing planting density and postponing the supplementary application of fertilizers. However, with an increase in planting density, the demand of N increased along with grain yield. Due to the input of too much N fertilizer, the efifciency of N use in SH was low. Applying less total N, ameliorating cultivation and cropping management practices should be considered as priority strategies to augment production potential and ifnal y achieve synchronization between high yield and high N efifciency in fertile soils. However, in situations where soil fertility is low, achieving high yield and high N use efifciency in maize wil likely depend on increased planting density and appropriate application of supplementary fertilizers postpone to the grain-ifl ing stage.

  7. Six month-duration Tephrosia vogelii Hook. f. and Tithonia diversifolia (Hemsl. A. Gray planted-fallows for improving maize production in Kenya

    Directory of Open Access Journals (Sweden)

    Gachene C.K.K.

    2008-01-01

    Full Text Available An experiment including planted Tephrosia vogelii and Tithonia diversifolia fallow species and natural fallow was conducted at Maseno, Kenya, for assessing whether these fallows grown on a nutrient depleted land could produce sufficient green manure in six month period, whether their biomass retained on the same plots or transferred to continuously cropped plots with or without added P fertiliser could increase yield of consecutive maize crops and whether it is useful to regularly repeat these fallows on same plots. First fallow was established in randomized complete blocks with three replicates. At harvesting, biomass was recorded, then either incorporated in situ or transferred to continuous cropped plots split with and without added P fertiliser and monitored for the effect in improving consecutive maize crops. The second fallow was managed on this split plot design. The two-planted shrubs fallows produced more than 9 Mg total dry biomass and accumulated 154 to 234 kg N.ha-1, which were significantly higher compared to the production in the natural fallow. The shrubs were also superior to natural fallow for P accumulation (5-22 kg versus 2 kg.ha-1. The aboveground dry biomass harvested from planted T. vogelii and T. diversifolia and either incorporated in situ or transferred into continuously cropped plots increased maize yields by 2.5 folds compared to the unmanured crop, the control. Supplementing the organic materials with an additional 20 kg P inorganic fertilizer increased the 1st maize yield by about 40%. Productivity in the plots with T. vogelii or T. diversifolia aboveground biomass removal was low for the subsequent fallow and maize crops when compared to the performance in plots where biomass was incorporated. To achieve sustained yields of maize in depleted soils requires regular improved fallowing at least one season alternating with one season maize, and additional P inputs.

  8. Chitosan/halloysite nanotubes bionanocomposites: structure, mechanical properties and biocompatibility.

    Science.gov (United States)

    Liu, Mingxian; Zhang, Yun; Wu, Chongchao; Xiong, Sheng; Zhou, Changren

    2012-11-01

    Incorporation of nanosized reinforcements into chitosan usually results in improved properties and changed microstructures. Naturally occurred halloysite nanotubes (HNTs) are incorporated into chitosan for forming bionanocomposite films via solution casting. The electrostatic attraction and hydrogen bonding interactions between HNTs and chitosan are confirmed. HNTs are uniformly dispersed in chitosan matrix. The tensile strength and Young's modulus of chitosan are enhanced by HNTs. The storage modulus and glass transition temperature of chitosan/HNTs films also increase significantly. Blending with HNTs induces changes in surface nanotopography and increase of roughness of chitosan films. In vitro fibroblasts response demonstrates that both chitosan and chitosan/HNTs nanocomposite films are cytocompatibility even when the loading of HNTs is 10%. In summary, these results provide insights into understanding of the structural relationships of chitosan/HNTs bionanocomposite films in potential applications, such as scaffold materials in tissue engineering. PMID:22743347

  9. Application of organic matter and biofertilizer to improve growth and yield of maize on soil damaged by volcanic ash of Mount Kelud in East Java

    Directory of Open Access Journals (Sweden)

    S. Hardianita

    2015-07-01

    Full Text Available Volcanic ash from the eruption of Mount Kelud in 2014 damaged some agricultural areas grown with maize in Malang of East Java. The purpose of this study was to elucidate the effect of organic fertilizers and biological fertilizers on growth and yield of maize on soils damaged by volcanic ash from the eruption of Mount Kelud. A pot experiment was conducted in the glasshouse of Balitkabi, Kendalpayak, Malang from July 2014 to February 2015. The treatments tested in this study were combinations of three mixtures of soil and volcanic ash (90%:10%, 80%:20%, and 70%:30%, and two doses of biofertilizer (25 and 35 kg / ha. Each treatment was added with 5 t organic matter/ha. A total of 10 kg of each mixture of soil and volcanic ash was placed in a 15 kg plastic pot. Each treatment received 100 kg inorganic fertilizer / kg containing 15% N, 15% P, and 15% K. Three seeds of maize (NK33 variety were planted in each pot and thin to one plant after one week. The experiment was conducted for 14 weeks. The results showed that application of organic matter and biofertilizer did not significantly improve fertility of soil mixed with volcanic ash from the eruption of Mount Kelud. Yield of maize was not significantly improved by the application of organic matter and biofertilizer on soil mixed with volcanic ash. The contents of carbohydrates and proteins in maize seeds were also not affected by application of organic matter and biofertilizer.

  10. Chitosan hydrogel beads impregnated with hexadecylamine for improved reactive blue 4 adsorption.

    Science.gov (United States)

    Vakili, Mohammadtaghi; Rafatullah, Mohd; Ibrahim, Mahamad Hakimi; Abdullah, Ahmad Zuhairi; Salamatinia, Babak; Gholami, Zahra

    2016-02-10

    Adsorption performance of chitosan (CS) hydrogel beads was investigated after impregnation of CS with hexadecylamine (HDA) as a cationic surfactant, for the elimination of reactive blue 4 (RB4) from wastewater. The CS/HDA beads formed with 3.8% HDA were the most effective adsorbent. The adsorption capacity was increased by 1.43 times from 317 mg/g (CS) to 454 mg/g (CS/HDA). The RB4 removal increased with decrease in the pH of dye solution from 4 to 9. The isotherm data obtained from RB4 adsorption on CS and CS/HDA are adequately described by Freundlich model (R(2)=0.946 and 0.934, χ(2)=22.414 and 64.761). The kinetic study revealed that the pseudo-second-order rate model (R(2)=0.996 and 0.997) was in better agreement with the experimental data. The negative values of ΔG° (-2.28 and -6.30 kJ/mol) and ΔH° (-172.18 and -101.62 kJ/mol) for CS beads and HDA modified CS beads, respectively; suggested a spontaneous and exothermic process for RB4 adsorption. PMID:26686114

  11. Superparamagnetic iron oxide/chitosan core/shells for hyperthermia application: Improved colloidal stability and biocompatibility

    Science.gov (United States)

    Patil, R. M.; Shete, P. B.; Thorat, N. D.; Otari, S. V.; Barick, K. C.; Prasad, A.; Ningthoujam, R. S.; Tiwale, B. M.; Pawar, S. H.

    2014-04-01

    Superparamagnetic magnetite nanoparticles are of great interest due to their potential biomedical applications. In the present investigation, Fe3O4 magnetic nanoparticles were prepared by alkaline precipitation using ferrous chloride as the sole source. An amphiphilic polyelectrolyte with the property of biocompatibility and functional carboxyl groups was used as a stabilizer to prepare a well-dispersed suspension of superparamagnetic Fe3O4 nanoparticles. The final material composed of Fe3O4 core and chitosan (CH) shell was produced. The amino groups of CH coated on Fe3O4 nanoparticles were further cross linked using glutaraldehyde (GLD) for stable coating. FTIR spectra, XPS and TGA confirmed the coating of CH/GLD on the surface of Fe3O4 nanoparticles. XRD patterns indicate the pure phase Fe3O4 with a spinel structure. The nanoparticles were superparamagnetic at room temperature with saturation magnetization values for bare and coated nanoparticles which were 51.68 emu/g and 48.60 emu/g, respectively. Zeta potential values showed higher colloidal stability of coated nanoparticles than the bare one. Cytotoxicity study up to 2 mg mL-1 concentration showed no drastic change in cell viability of nanoparticles after coating. Also, coated nanoparticles showed increased SAR value, making them suitable for hyperthermia therapy application.

  12. Integrated genetic maps of DNA markers and mutations and their utility for improving sorghum and maize

    International Nuclear Information System (INIS)

    The primary goal of this research programme was to develop basic genetic tools for facilitating research in the genetics and breeding of sorghum. The restriction fragment length polymorphism (RFLP) linkage map produced at Iowa State University was created through linkage analysis of 78 F2 plants of an intraspecific cross between inbred CK60 and accession PI229828. The map consists of 201 loci distributed among 10 linkage groups covering 1299 cM. Comparison of sorghum and maize RFLP maps revealed a high degree of conservation, as reflected by homology, copy number and collinearity. Examples of conserved and rearranged locus orders were observed. The same sorghum population was used to map the genetic factors (mutants and quantitative trait loci (QTL)) for several traits, including vegetative and reproductive morphology, maturity, and insect and disease resistance. Analysis of the genetic factors affecting plant height, an important character for sorghum adaptation in temperate latitudes for grain production, is emphasized. Four QTL for plant height were identified in a sample of 152 F2 plants, whereas six QTL were detected among their F3 progeny. These observations and assessments of other traits at four QTL common to the F2 plants and their F3 progeny indicate that some of these regions correspond to loci (dw) previously identified on the basis of alleles with highly qualitative effects. Four of the six sorghum plant height QTL seem to be orthologous to plant height QTL in maize. Other possible instances of orthologous QTL included regions for maturity and tillering. These observations suggest that conservation of the maize and sorghum genomes encompasses sequence homology, collinearity and function. 11 refs, 2 figs

  13. Altered Lignin Biosynthesis Improves Cellulosic Bioethanol Production in Transgenic Maize Plants Down-Regulated for Cinnamyl Alcohol Dehydrogenase

    Institute of Scientific and Technical Information of China (English)

    Silvia Fornalé; Pere Puigdomènech; Joan Rigau; David Caparrós-Ruiz; Montserrat Capellades; Antonio Encina; Kan Wang; Sami Irar; Catherine Lapierre; Katia Ruel; Jean-Paul Joseleau; Jordi Berenguer

    2012-01-01

    Cinnamyl alcohol dehydrogenase(CAD)is a key enzyme involved in the last step of monolignol biosynthesis.The effect of CAD down-regulation on lignin production was investigated through a transgenic approach in maize.Transgenic CAD-RNAi plants show a different degree of enzymatic reduction depending on the analyzed tissue and show alterations in cell wall composition.Cell walls of CAD-RNAi stems contain a lignin polymer with a slight reduction in the S-to-G ratio without affecting the total lignin content.In addition,these cell walls accumulate higher levels of cellulose and arabinoxylans.In contrast,cell walls of CAD-RNAi midribs present a reduction in the total lignin content and of cell wall polysaccharides.In vitro degradability assays showed that,although to a different extent,the changes induced by the repression of CAD activity produced midribs and stems more degradable than wild-type plants.CAD-RNAi plants grown in the field presented a wild-type phenotype and produced higher amounts of dry biomass.Cellulosic bioethanol assays revealed that CAD-RNAi biomass produced higher levels of ethanol compared to wild-type,making CAD a good target to improve both the nutritional and energetic values of maize lignocellulosic biomass.

  14. IMPROVEMENT OF RESPONSE TO LOW WATER AVAILABILITY IN MAIZE PLANTS INOCULATED WITH SELECTED RHIZOSPHERIC MICROBIAL CONSORTIA UNDER DIFFERENT IRRIGATION REGIMES

    Directory of Open Access Journals (Sweden)

    Eligio Malusà

    2014-01-01

    Full Text Available Low water availability for agriculture is a rising problem in temperate countries. The effect of two different rhizospheric microbial consortia on the tolerance to water deficiency of maize was evaluated under controlled watering regimes. One consortium was a mixture of arbuscular mycorrhizal fungi and rhizospheric bacteria isolated under osmotic stress selective pressure; the other consortium was a commercial product. A higher tolerance of plants to water deficiency was observed when roots were inoculated with microbial consortia. Plant gas exchange parameters were positively affected by inoculation, and a improvements of the leaves mineral nutrients content and of the biomass yield were also recorded. The positive effect should be ascribed to an increased roots development more than to an increased uptake from extraradical mycorrhizal hyphae. The use of microbial inoculants appears to be a suitable practice to improve the crop performances under low water availability.

  15. Improving solubility, stability, and cellular uptake of resveratrol by nanoencapsulation with chitosan and γ-poly (glutamic acid).

    Science.gov (United States)

    Jeon, Young Ok; Lee, Ji-Soo; Lee, Hyeon Gyu

    2016-11-01

    Resveratrol (RES), a polyphenolic compound found in grape skins, is a potent antioxidant with broad health benefits. However, its utilization in food has been limited by its poor water solubility, instability, and low bioavailability. The purpose of this study is to improve the solubility, stability, and cellular uptake of RES by nanoencapsulation using chitosan (CS) and γ-poly (glutamic acid) (γ-PGA). The size of nanoparticles significantly decreases with a decrease in the CS/γ-PGA ratio (p<0.05). The nanoparticle size with CS/γ-PGA ratio of 5 was 100-150nm. The entrapment efficiency and UV-light protection effect significantly increases (p<0.05), with an increase in the CS and γ-PGA concentration. The solubility of RES increases 3.2 and 4.2 times before and after lyophilization by nanoencapsulation, respectively. Compared with non-nanoencapsulated RES, the nanoencapsulated RES tends to maintain its solubility and antioxidant activity during storage. CS/γ-PGA nanoencapsulation was able to significantly enhance the transport of RES across a Caco-2 cell monolayer (p<0.05). The highest cellular uptake was found for nanoparticles prepared with 0.5mg/mL CS and 0.1mg/mL γ-PGA, which showed the highest solubility and antioxidant activity during storage. Therefore, CS/γ-PGA nanoencapsulation is found to be a potentially valuable technique for improving the solubility, stability, and cellular uptake of RES. PMID:27518454

  16. Improved wettability and adhesion of polylactic acid/chitosan coating for bio-based multilayer film development

    Science.gov (United States)

    Gartner, Hunter; Li, Yana; Almenar, Eva

    2015-03-01

    The objective of this study was to investigate the effect of methyldiphenyl diisocyanate (MDI) concentration (0, 0.2, 1, 2, and 3%) on the wettability and adhesion of blend solutions of poly(lactic acid) (PLA) and chitosan (CS) when coated on PLA film for development of a bio-based multi-layer film suitable for food packaging and other applications. Characterization was carried out by attenuated total reflectance infrared spectrometry (ATR-FTIR), contact angle (θ), mechanical adhesion pull-off testing, and scanning electron microscopy (SEM). The θ of the PLA/CS blend shifted to a lower value (41-35°) with increasing MDI concentration showing that the surface tension was modified between the PLA/CS blend solution and PLA film and better wettability was achieved. The increase in MDI also resulted in an increased breaking strength (228-303 kPa) due to the increased H-bonding resulting from the more urethane groups formed within the PLA/CS blend as shown by ATR-FTIR. The improved adhesion was also shown by the increased number of physical entanglements observed by SEM. It can be concluded that MDI can be used to improve wettability and adhesion between PLA/CS coating and PLA film.

  17. Improving the controlled delivery formulations of caffeine in alginate hydrogel beads combined with pectin, carrageenan, chitosan and psyllium.

    Science.gov (United States)

    Belščak-Cvitanović, Ana; Komes, Draženka; Karlović, Sven; Djaković, Senka; Spoljarić, Igor; Mršić, Gordan; Ježek, Damir

    2015-01-15

    Alginate-based blends consisting of carrageenan, pectin, chitosan or psyllium husk powder were prepared for assessment of the best formulation aimed at encapsulation of caffeine. Alginate-pectin blend exhibited the lowest viscosity and provided the smallest beads. Alginate-psyllium husk blend was characterised with higher viscosity, yielding the largest bead size and the highest caffeine encapsulation efficiency (83.6%). The release kinetics of caffeine indicated that the porosity of alginate hydrogel was not reduced sufficiently to retard the diffusion of caffeine from the beads. Chitosan coated alginate beads provided the most retarded release of caffeine in water. Morphological characteristics of beads encapsulating caffeine were adversely affected by freeze drying. Bitterness intensity of caffeine-containing beads in water was the lowest for alginate-psyllium beads and chitosan coated alginate beads. Higher sodium alginate concentration (3%) for production of hydrogel beads in combination with psyllium or chitosan coating would present the most favourable carrier systems for immobilization of caffeine.

  18. Encapsulation of selenium in chitosan nanoparticles improves selenium availability and protects cells from selenium-induced DNA damage response

    Science.gov (United States)

    Selenium, an essential mineral, plays important roles in optimizing human health. Chitosan is an effective, naturally oriented material for synthesizing nanoparticles with polyanions and exhibit preferable properties such as biocompatibility, biodegradation and resistance to certain enzymes. We have...

  19. Improvement of the microbiological quality of ready-to-eat peeled shrimps (Penaeus vannamei) by the use of chitosan coatings.

    Science.gov (United States)

    Carrión-Granda, Ximena; Fernández-Pan, Idoya; Jaime, Isabel; Rovira, Jordi; Maté, Juan I

    2016-09-01

    Chitosan coatings incorporated with 0.5% of oregano and thyme EO were applied onto ready-to-eat peeled shrimp tails and packed under MAP conditions. The growth of naturally present spoilage microorganisms was evaluated for 12days during chilled storage (4°C). Coatings containing thyme EO were more effective in inhibiting the microbial species studied, specially lactic acid and psychrotrophic bacteria. As carrier of EOs, chitosan was more effective in inhibiting the growth of bacteria present in peeled shrimps than the direct application of an oil-water (O/W) emulsion. Finally, results from sensory analysis showed that the sensorial quality was affected by the chitosan-thyme coatings despite characteristics like firmness and colour were kept. The present work demonstrates the effectiveness of chitosan enriched coatings, offering a promising alternative to control the growth of spoilage and pathogen microorganisms on peeled shrimps during refrigeration storage. PMID:27315588

  20. Improvement to Maize Growth Caused by Biochars Derived From Six Feedstocks Prepared at Three Different Temperatures

    Institute of Scientific and Technical Information of China (English)

    LUO Yu; JIAO Yu-jie; ZHAO Xiao-rong; LI Gui-tong; ZHAO Li-xin; MENG Hai-bo

    2014-01-01

    Biochar is increasingly proposed as a soil amendment, with reports of benefits to soil physical, chemical and biological properties. In this study, different biochars were produced from 6 feedstocks, including straw and poultry manure, at 3 pyrolysis temperatures (200, 300 and 500°C) and then added separately to a calcareous soil. Their effects on soil properties and maize growth were evaluated in a pot experiment. The biochars derived from crop straw had much higher C but smaller N concentrations than those derived from poultry manure. Carbon concentrations, pH and EC values increased with increasing pyrolysis temperature. Biochar addition resulted in increases in mean maize dry matter of 12.73%and NPK concentrations of 30, 33 and 283%, respectively. Mean soil pH values were increased by 0.45 units. The biochar-amended soils had 44, 55, 254 and 537%more organic C, total N, Olsen-P and available K, respectively, than the control on average. Both feedstocks and pyrolysis temperature determined the characteristics of the biochar. Biochars with high mineral concentrations may act as mineral nutrient supplements.

  1. Role of chitosan in improving salinity resistance through some morphological and physiological characteristics in fenugreek (Trigonella foenum-graecum L.

    Directory of Open Access Journals (Sweden)

    H. Mosapour Yahyaabadi

    2016-06-01

    Full Text Available Soil salinity is a serious environmental problem that has negative impacts on growth and production of plants. On the other hand, application of chitosan has recently been increased to enhance the resistance to different stresses, such as salinity. In order to study the effect of chitosan seed-priming on alleviation of salinity stress in fenugreek (Trigonella foenum-graecum L. a factorial experiment, based on completely randomized design with three replications, was conducted in 2014 in the Research Greenhouse of University of Zabol. Chitosan pretreatment, taken as the first factor, was applied at three levels (0, 0.5 and 1 g/l and sodium chloride (NaCl was the second factor at four levels (0, 50, 150 and 250 mM. Before planting, the seeds were soaked for 6 hours in the chitosan solutions. NaCl was applied to the plants by irrigation water (after 2-leaf stage, with 3-day intervals. Results indicated that increasing salinity stress reduced growth characteristics, content of photosynthetic pigments, leaf relative water content, chlorophyll index and increased the amount of anthocyanin and proline. Seed-pretreatment by application of 0.5 mg/L chitosan, under salinity stress, increased plant dry weight, length of stem and roots, and leaf relative water content, as compared to the control treatment. In addition, under the salinity level of 250 mM, application of 1 g/L chitosan increased chlorophyll a, chlorophyll b and carotenoids content by 43.7, 65.4 and 28 percent, respectively, as compared to the control treatment. The highest amount of anthocyanin was found in the 1 g/L chitosan treatment. In general, these results suggested that in salt-affected areas, seed pretreatment by application of chitosan could be utilized efficiently for reducing the salinity stress on leaf relative water content and photosynthetic pigments, and better growth and stablishment of fenugreek plant.

  2. Ammonia volatilization from enhanced-efficiency urea on no-till maize in brazilian cerrado with improved soil fertility

    Directory of Open Access Journals (Sweden)

    Eduardo Lopes Cancellier

    2016-04-01

    Full Text Available ABSTRACT High nitrogen losses by ammonia volatilization are expected when urea is used as the source of N. The use of controlled-release urea and urease inhibitors are possible strategies to reduce such losses and increase nitrogen use efficiency. This study aimed to evaluate nitrogen losses by ammonia volatilization from stabilized, slow and controlled release urea and its absorption by maize grown under no-till in an improved Cerrado soil. Four N sources were used: conventional urea, urea + N-(n-butyl thiophosphoric triamide (NBPT, urea + Cu and B and urea coated by sulfur + polymers. These N sources were surface applied along the rows using three N doses of 100, 150 and 200 kg ha-1. No N was added to the control. Data were collected regarding N losses by volatilization, the N contents accumulated in the stubble and grains, and the yields of the stubble and grains. Stabilized urea and slow release urea were efficient for postponing the ammonia volatilization peaks. The urease inhibitors postponed the peaks for up to two days, reducing the accumulated volatilization by 18% when compared with common urea. Polymer sulfur coated urea resulted in a 37% reduction in ammonia volatilization. Increasing the N application rate to 200 kg ha-1 resulted in 16% greater yields and 37% greater N accumulation in the plants relative to the control. However, the stabilized and slow-release urea did not improve the N accumulation or yield. Consequently, the nitrogen use efficiency of maize was not improved relative to the use of conventional urea.

  3. Mineral N dynamics, leaching and nitrous oxide losses under maize following two-year improved fallows on a sandy loam soil in Zimbabwe

    NARCIS (Netherlands)

    Chikowo, R.; Mapfumo, P.; Nyamugafata, P.; Giller, K.E.

    2004-01-01

    The fate of the added N on a sandy loam soil was determined in an improved fallow - maize sequence field experiment in Zimbabwe. Pre-season mineral N was determined in 20 cm sections to 120 cm depth by soil auguring in seven land use systems. Thereafter, sequential soil auguring was done at two-week

  4. Prof. Wang Jie Met with the Chair of Board of Trustees and the Director General of International Maize and Wheat Improvement Center

    Institute of Scientific and Technical Information of China (English)

    Zhang Yongtao

    2007-01-01

    @@ On April 10, 2007, Prof. Wang Jie, Vice President of NSFC, met with the delegation from International Maize and Wheat Improvement Center (CIMMYT), headed by its Chair of Board of Trustees Prof. Lene Lange and the Director General Prof. Masa Iwanaga.

  5. Improved wettability and adhesion of polylactic acid/chitosan coating for bio-based multilayer film development

    Energy Technology Data Exchange (ETDEWEB)

    Gartner, Hunter [School of Packaging, Michigan State University, East Lansing, Michigan (United States); Li, Yana [Mechanical Engineering College, Wuhan Polytechnic University (China); Almenar, Eva, E-mail: ealmenar@msu.edu [School of Packaging, Michigan State University, East Lansing, Michigan (United States)

    2015-03-30

    Graphical abstract: - Highlights: • Surface tension between PLA/CS blend solution and PLA film modified by MDI. • Better wettability between PLA/CS blend solution and PLA film by increasing MDI. • Increased breaking strength by increasing MDI due to the increased H-bonding. • Increased number of physical entanglements between PLA/CS coating and PLA film. • Development of a suitable bio-based multilayer film for food packaging applications. - Abstract: The objective of this study was to investigate the effect of methyldiphenyl diisocyanate (MDI) concentration (0, 0.2, 1, 2, and 3%) on the wettability and adhesion of blend solutions of poly(lactic acid) (PLA) and chitosan (CS) when coated on PLA film for development of a bio-based multi-layer film suitable for food packaging and other applications. Characterization was carried out by attenuated total reflectance infrared spectrometry (ATR-FTIR), contact angle (θ), mechanical adhesion pull-off testing, and scanning electron microscopy (SEM). The θ of the PLA/CS blend shifted to a lower value (41–35°) with increasing MDI concentration showing that the surface tension was modified between the PLA/CS blend solution and PLA film and better wettability was achieved. The increase in MDI also resulted in an increased breaking strength (228–303 kPa) due to the increased H-bonding resulting from the more urethane groups formed within the PLA/CS blend as shown by ATR-FTIR. The improved adhesion was also shown by the increased number of physical entanglements observed by SEM. It can be concluded that MDI can be used to improve wettability and adhesion between PLA/CS coating and PLA film.

  6. Improving the efficiency of use of small amounts of nitrogen and phosphorus fertilizer on smallholders maize in Central Malawi

    NARCIS (Netherlands)

    Kamanga, B.C.G.; Waddington, S.R.; Almekinders, C.J.M.; Giller, K.E.

    2014-01-01

    Mineral fertiliser is a scarce input for smallholder maize farmers in Malawi. A recent provision of small amounts of subsidised fertilisers by government programmes to farmers throughout Malawi has increased fertiliser access and raised maize production, but fertiliser management and yield responses

  7. Exploration of agro-ecological options for improving maize-based farming systems in Costa Chica, Guerrero, Mexico

    OpenAIRE

    Flores Sanchez, D.

    2013-01-01

    Keywords: farm diagnosis, farming systems, soil degradation, intercropping, maize, roselle, legumes, nutrient management, vermicompost, crop residues, decomposition, explorations.   In the Costa Chica, a region of Southwest Mexico, farming systems are organized in smallholder units. The dominant cropping systems are based on maize (Zea mays L.), either as monocrop or intercropped with roselle (Hibiscus sabdariffa L.). Continuous cropping, and unbalanced fertilizer management systems with...

  8. Use of wheat and maize protein mutants in breeding for improved protein quantity and quality

    International Nuclear Information System (INIS)

    Selected offspring progenies (50 mutant lines) originating from mutation experiments with hexaploid wheat (cv. Bezostaya 1) were analysed for induced heritable variation in protein content, lysine content, grain yield and protein and lysine yields. Ten of these mutant lines were crossed with 11 local varieties. The protein and lysine contents were measured in the progenies of these crossings. The data showed better correlations of grain yield with protein and lysine yields than the protein and lysine contents with their corresponding yields. F1 seeds showed higher lysine and protein contents than local varieties. Data with maize showed that: (1) the total endosperm protein content of modified opaque-2 types increases with an increase in the degree of normalization; (2) the lysine content in dry matter and protein in normalized o2 kernels usually decreases with the increasing degree of normalization; (3) the lysine content in protein of modified o2 kernels, is, in general, satisfactory up to the normalization of about 50% of endosperm. A desirable modification of o2 endosperm within line A632o2 was selected and crossed with o2 lines. Most of the tested hybrids had a good protein quality, but endosperm modification was not evident in all hybrids. The o2 gene was incorporated into high protein backgrounds. Besides a high protein content and quality, some of the hybrids tested had a comparable or higher yield than the o2 check. (author)

  9. Blood protein adsorption onto chitosan

    OpenAIRE

    Benesch, Johan; Tengvall, P.

    2002-01-01

    Chitosan was recently indicated to enhance osteogenesis, improve wound healing but to activate the coagulation and the complement systems. In the present study approximately 10nm thick chitosan film were prepared on aminopropyltriethoxysilane (APTES) coated silicon. The surfaces were incubated in serum or plasma and subsequently in antibodies towards key complement and contact activation of coagulation proteins. The deposited amounts were compared with those on hydrophilic and hydrop...

  10. A review on chitosan-cellulose blends and nanocellulose reinforced chitosan biocomposites: Properties and their applications.

    Science.gov (United States)

    H P S, Abdul Khalil; Saurabh, Chaturbhuj K; A S, Adnan; Nurul Fazita, M R; Syakir, M I; Davoudpour, Y; Rafatullah, M; Abdullah, C K; M Haafiz, M K; Dungani, R

    2016-10-01

    Chitin is one of the most abundant natural polymers in world and it is used for the production of chitosan by deacetylation. Chitosan is antibacterial in nature, non-toxic, and biodegradable thus it can be used for the production of biodegradable film which is a green alternative to commercially available synthetic counterparts. However, their poor mechanical and thermal properties restricted its wide spread applications. Chitosan is highly compatible with other biopolymers thus its blending with cellulose and/or incorporation of nanofiber isolated from cellulose namely cellulose nanofiber and cellulose nanowhiskers are generally useful. Cellulosic fibers in nano scale are attractive reinforcement in chitosan to produce environmental friendly composite films with improved physical properties. Thus chitosan based composites have wide applicability and potential in the field of biomedical, packaging and water treatment. This review summarises properties and preparation procedure of chitosan-cellulose blends and nano size cellulose reinforcement in chitosan bionanocomposites for different applications. PMID:27312632

  11. A review on chitosan-cellulose blends and nanocellulose reinforced chitosan biocomposites: Properties and their applications.

    Science.gov (United States)

    H P S, Abdul Khalil; Saurabh, Chaturbhuj K; A S, Adnan; Nurul Fazita, M R; Syakir, M I; Davoudpour, Y; Rafatullah, M; Abdullah, C K; M Haafiz, M K; Dungani, R

    2016-10-01

    Chitin is one of the most abundant natural polymers in world and it is used for the production of chitosan by deacetylation. Chitosan is antibacterial in nature, non-toxic, and biodegradable thus it can be used for the production of biodegradable film which is a green alternative to commercially available synthetic counterparts. However, their poor mechanical and thermal properties restricted its wide spread applications. Chitosan is highly compatible with other biopolymers thus its blending with cellulose and/or incorporation of nanofiber isolated from cellulose namely cellulose nanofiber and cellulose nanowhiskers are generally useful. Cellulosic fibers in nano scale are attractive reinforcement in chitosan to produce environmental friendly composite films with improved physical properties. Thus chitosan based composites have wide applicability and potential in the field of biomedical, packaging and water treatment. This review summarises properties and preparation procedure of chitosan-cellulose blends and nano size cellulose reinforcement in chitosan bionanocomposites for different applications.

  12. Blood contact properties of ascorbyl chitosan.

    Science.gov (United States)

    Yalinca, Z; Yilmaz, E; Taneri, B; Bullici, F; Tuzmen, S

    2013-01-01

    Ascorbyl chitosan was synthesized by heating chitosan with ascorbic acid in isopropanol. The products were characterized by FTIR and C-13 NMR spectroscopies, SEM, and elemental analysis. Blood contact properties of ascorbyl chitosans were evaluated. The ascorbyl chitosans demonstrated to have increased lipid-lowering activity in comparison to chitosan alone upon contact with human blood serum in in vitro conditions. Furthermore, the total cholesterol/HDL ratio was improved towards the desirable ideal values after three hours contact with ascorbyl chitosan samples. The lipid-lowering activity increased with ascorbyl substitution. The inherent nonspecific adsorption capability of chitosan due to its chelating power with several different functional groups was exhibited by ascorbyl chitosans as well. This behavior was exemplified in a simultaneous decrease in the total iron values of the volunteers together with lower lipid levels. Furthermore, ascorbyl chitosans were observed to have less hemocompatibility but increased anticoagulant activity when compared to chitosan alone. Additional in vivo studies are necessary to support these results and to investigate further the advantages and disadvantages of these materials to prove their safety prior to clinical applications. PMID:23862665

  13. Liposomes coated with N-trimethyl chitosan to improve the absorption of harmine in vivo and in vitro.

    Science.gov (United States)

    Chen, Wei-Liang; Yuan, Zhi-Qiang; Liu, Yang; Yang, Shu-di; Zhang, Chun-ge; Li, Ji-Zhao; Zhu, Wen-jing; Li, Fang; Zhou, Xiao-feng; Lin, Yi-mei; Zhang, Xue-nong

    2016-01-01

    In this study, harmine liposomes (HM-lip) were prepared through the thin-film hydration-pH-gradient method and then coated with N-trimethyl chitosan (TMC). Particle size, zeta potential, entrapment efficiency, and in vitro release of HM-lip and TMC-coated harmine liposomes (TMC-HM-lip) were also determined. Sprague Dawley rats were further used to investigate the pharmacokinetics in vivo. Retention behavior in mouse gastrointestinal tract (GIT) was studied through high-performance liquid chromatography and near-infrared imaging. Degradation was further evaluated through incubation with Caco-2 cell homogenates, and a Caco-2 monolayer cell model was used to investigate the uptake and transport of drugs. HM-lip and TMC-HM-lip with particle size of 150-170 nm, an entrapment efficiency of about 81%, and a zeta potential of negative and positive, respectively, were prepared. The release of HM from HM-lip and TMC-HM-lip was slower than that from HM solution and was sensitive to pH. TMC-HM-lip exhibited higher oral bioavailability and had prolonged retention time in GIT. HM-lip and TMC-HM-lip could also protect HM against degradation in Caco-2 cell homogenates. The uptake amount of TMC-HM-lip was higher than that of HM and HM-lip. TMC-HM-lip further demonstrated higher apparent permeability coefficient (P(app)) from the apical to the basolateral side than HM and HM-lip because of its higher uptake and capability to open tight junctions in the cell monolayers. TMC-HM-lip can prolong the retention time in the GIT, protect HM against enzyme degradation, and improve transport across Caco-2 cell monolayers, thus enhancing the oral bioavailability of HM. PMID:26855571

  14. Chitosan composite films. Biomedical applications.

    Science.gov (United States)

    Cárdenas, Galo; Anaya, Paola; von Plessing, Carlos; Rojas, Carlos; Sepúlveda, Jackeline

    2008-06-01

    Chitosan acetate films have been prepared using chitosans from shrimps (Pleuroncodes monodon) of low and high molecular weight (LMv = 68,000 g/mol and HMv = 232,000 g/mol) and deacetylation degree of 80 and 100%, respectively. The chitosan films were obtained by addition of several additives to acetic acid chitosan solutions, such as: glycerol, oleic acid and linoleic acid in different proportions. The pH of the solutions before casting ranged from 5.0 to 6.0. The composite film thickness are reported. The films have been analyzed by FTIR showing characteristic bands corresponding to the additives. The scanning electron microscopy (SEM) studies reveals the different morphology of the composite films. The films exhibit different physical properties depending upon the additives and/or mixture of them. The addition of glycerol to composite improves the elasticity of the films. The swelling in glucose and saline solutions for several films was evaluated, being higher in the glucose solution. The bactericide test against Staphylococcus aureus, Pseudomona aeruginosa and Acinetobacter baumanii in plates with either blood and or agar tripticase showed that the molecular weight influences on the bactericidal properties of the chitosan composite films and over its effect against gram positive and gram negative bacteria. Medical applications of the composite films were done in patients with burns, ulcers and injuries, the films containing glycerol showed good adhesion in comparison with those without it. The composite films tested were mainly three (1) chitosan acetate with glycerol, (2) chitosan acetate with oleic acid and (3) chitosan acetate with glycerol and oleic acid. Excellent results in the skin recovery were obtained after 7-10 days. Since the chitosan is biodegradable by the body enzymes it does not need to be removed and increases the gradual grows of the damage tissues. PMID:18165888

  15. Integrated application of February Orchid (Orychophragmus violaceus) as green manure with chemical fertilizer for improving grain yield and reducing nitrogen losses in spring maize system in northern China

    Institute of Scientific and Technical Information of China (English)

    BAI Jin-shun; CAO Wei-dong; XIONG Jing; ZENG Nao-hua; GAO Song-juan; Shimizu Katsuyoshi

    2015-01-01

    The development of more efifcient management systems is crucial to achieving high grain yields with high nitrogen use efifciency (NUE). February Orchid-spring maize rotation system is a newly established planting system with the beneifts of ground cover and potential wind erosion in northern China. A ifeld experiment was conducted to evaluate the effects of integrated application of February Orchid as green manure with reduction of chemical fertilizers (INTEGRATED) on spring maize yield, N uptake, ammonium volatilization, and soil residual mineral N in northern China. Compared to farmers’ traditional fertilization (CON), integrated application of February Orchid as green manure with 30% reduction of nitrogen fertilizers (INTEGRATED) increased maize grain yield and biomass by 9.9 and 10.2%, respectively. The 0–100 cm soil residual Nmin at harvest was decreased by 58.5% and thus nitrogen use efifciency was increased signiifcantly by 26.7%. The nitrogen balance calculation further demonstrated that the INTEGRATED approach performed better than CON with lower apparent nitrogen loss (decreased by 48.9%) which evidenced by the ammonium volatilization of top-dressing fertilizer was decreased by 31.1%, the Nmin movement to the deeper soil layers was reduced, and the apparent nitrogen leaching loss nearly equal to 0 under the INTEGRATED treatment. Therefore, in northern China, integrated application of green manure and chemical fertilizers is an efifcient management approach for improving maize yields and NUE simultaneously.

  16. Preparation of chitosan nanofibers from completely deacetylated chitosan powder by a downsizing process.

    Science.gov (United States)

    Aklog, Yihun Fantahun; Dutta, Ajoy Kumar; Izawa, Hironori; Morimoto, Minoru; Saimoto, Hiroyuki; Ifuku, Shinsuke

    2015-01-01

    Chitosan nanofibers were easily prepared from fully deacetylated chitosan dry powder using a high-pressure waterjet system. From SEM observation, after 10 cycles of treatment, most of the chitosan had been reduced to homogeneous nanofibers measuring tens of nanometers. On the other hand, further mechanical treatment did not show a significant change. Relative crystallinity of chitosan nanofibers gradually decreased as the number of passes increased since high-pressure waterjet treatment damaged the crystalline region of chitosan nanofibers. The transmittance of the chitosan nanofiber slurry increased steeply, as the number of passes increased, indicating that the chitosan fibers were disintegrated effectively. Viscosity of chitosan nanofiber slurry also showed that the chitosan disintegrated well into nanofibers up to 10 passes. Above 10 passes, disintegration efficiency was saturated. The molecular weights of the nanofibers steeply decreased due to the depolymerization of chitosan by mechanical disintegration. The Young's modulus and tensile strength of chitosan nanofiber sheets were improved as the number of treatments increased, but further treatments deteriorated the tensile strength. PMID:25450540

  17. Improvement of metal adsorption onto chitosan/Sargassum sp. composite sorbent by an innovative ion-imprint technology.

    Science.gov (United States)

    Liu, Huijuan; Yang, Fan; Zheng, Yuming; Kang, Jin; Qu, Jiuhui; Chen, J Paul

    2011-01-01

    Technology for immobilization of biomass has attracted a great interest due to the high sorption capacity of biomass for sequestration of toxic metals from industrial effluents. However, the currently practiced immobilization methods normally reduce the metal sorption capacities. In this study, an innovative ion-imprint technology was developed to overcome the drawback. Copper ion was first imprinted onto the functional groups of chitosan that formed a pellet-typed sorbent through the granulation with Sargassum sp.; the imprinted copper ion was chemically detached from the sorbent, leading to the formation of a novel copper ion-imprinted chitosan/Sargassum sp. (CICS) composite adsorbent. The copper sorption on CICS was found to be highly pH-dependent and the maximum uptake capacity was achieved at pH 4.7-5.5. The adsorption isotherm study showed the maximum sorption capacity of CICS of 1.08 mmol/g, much higher than the non-imprinted chitosan/Sargassum sp. sorbent (NICS) (0.49 mmol/g). The used sorbent was reusable after being regenerated through desorption. The FTIR and XPS studies revealed that the greater sorption of heavy metal was attributed to the large number of primary amine groups available on the surfaces of the ion-imprinted chitosan and the abundant carboxyl groups on Sargassum sp. Finally, an intraparticle surface diffusion controlled model well described the sorption history of the sorbents.

  18. Improving the controlled delivery formulations of caffeine in alginate hydrogel beads combined with pectin, carrageenan, chitosan and psyllium.

    Science.gov (United States)

    Belščak-Cvitanović, Ana; Komes, Draženka; Karlović, Sven; Djaković, Senka; Spoljarić, Igor; Mršić, Gordan; Ježek, Damir

    2015-01-15

    Alginate-based blends consisting of carrageenan, pectin, chitosan or psyllium husk powder were prepared for assessment of the best formulation aimed at encapsulation of caffeine. Alginate-pectin blend exhibited the lowest viscosity and provided the smallest beads. Alginate-psyllium husk blend was characterised with higher viscosity, yielding the largest bead size and the highest caffeine encapsulation efficiency (83.6%). The release kinetics of caffeine indicated that the porosity of alginate hydrogel was not reduced sufficiently to retard the diffusion of caffeine from the beads. Chitosan coated alginate beads provided the most retarded release of caffeine in water. Morphological characteristics of beads encapsulating caffeine were adversely affected by freeze drying. Bitterness intensity of caffeine-containing beads in water was the lowest for alginate-psyllium beads and chitosan coated alginate beads. Higher sodium alginate concentration (3%) for production of hydrogel beads in combination with psyllium or chitosan coating would present the most favourable carrier systems for immobilization of caffeine. PMID:25149001

  19. Improved stability and skin permeability of sodium hyaluronate-chitosan multilayered liposomes by Layer-by-Layer electrostatic deposition for quercetin delivery.

    Science.gov (United States)

    Jeon, Soha; Yoo, Cha Young; Park, Soo Nam

    2015-05-01

    Layer-by-Layer (LbL) technology, based on the electrostatic interaction of polyelectrolytes, is used to improve the stability of drug delivery systems. In the present study, we developed multilayered liposomes with up to 10 alternating layers based on LbL deposition of hyaluronate-chitosan for transdermal delivery. Dihexadecyl phosphate was used to provide liposomes with a negative charge; the liposomes were subsequently coated with cationic chitosan (CH) followed by anionic sodium hyaluronate (HA). The resulting particles had a cumulative size of 528.28±29.22nm and an alternative change in zeta potential. Differential scanning calorimetry (DSC) and transmission electron microscopy (TEM) revealed that the multilayered liposomes formed a spherical polyelectrolyte complex (PEC) after deposition. Observations in size distribution after 1 week found that the particles coated with even layers of polyelectrolytes, hyaluronate and chitosan (HA-CH), were more stable than the odd layers. Membrane stability in the presence of the surfactant Triton X-100 increased with an increase in bilayers as compared to uncoated liposomes. An increase in the number of bilayers deposited on the liposomal surface resulted in a sustained release of quercetin, with release kinetics that fit the Korsmeyer-Peppas model. In an in vitro skin permeation study, negatively charged (HA-CH)-L and positively charged CH-L were observed to have similar skin permeability, which were superior to uncoated liposomes. These results indicate that multilayered liposomes properly coated with polyelectrolytes of HA and CH by electrostatic interaction improve stability and can also function as potential drug delivery system for the transdermal delivery of the hydrophobic antioxidant quercetin. PMID:25819360

  20. Exploration of agro-ecological options for improving maize-based farming systems in Costa Chica, Guerrero, Mexico

    NARCIS (Netherlands)

    Flores Sanchez, D.

    2013-01-01

    Keywords: farm diagnosis, farming systems, soil degradation, intercropping, maize, roselle, legumes, nutrient management, vermicompost, crop residues, decomposition, explorations.   In the Costa Chica, a region of Southwest Mexico, farming systems are organized in smallholder

  1. Preparation, characterization and antibacterial activity of chitosan and phosphorylated chitosan from cuttlebone of Sepia kobiensis (Hoyle, 1885)

    OpenAIRE

    Annaian Shanmugam; Kandasamy Kathiresan; Lakshman Nayak

    2016-01-01

    Chitosan is a commercially available derivative of chitin that has been extensively studied for its antimicrobial properties. In order to improve the water solubility and its biological activity, the chemical modification or derivatisation is attempted. In the present investigation, the chitosan prepared from the cuttlebone of Sepia kobiensis was being chemically modified by reacting it with orthophosphoric acid so as to obtain phosphorylated chitosan. Then the chitosan and phosphorylated chi...

  2. An oral chitosan DNA vaccine against nodavirus improves transcription of cell-mediated cytotoxicity and interferon genes in the European sea bass juveniles gut and survival upon infection.

    Science.gov (United States)

    Valero, Yulema; Awad, Elham; Buonocore, Francesco; Arizcun, Marta; Esteban, M Ángeles; Meseguer, José; Chaves-Pozo, Elena; Cuesta, Alberto

    2016-12-01

    Vaccines for fish need to be improved for the aquaculture sector, with DNA vaccines and the oral administration route providing the most promising improvements. In this study, we have created an oral chitosan-encapsulated DNA vaccine (CP-pNNV) for the nodavirus (NNV) in order to protect the very susceptible European sea bass (Dicentrarchus labrax). Our data show that the oral CP-pNNV vaccine failed to induce serum circulating or neutralizing specific antibodies (immunoglobulin M) or to up-regulate their gene expression in the posterior gut. However, the vaccine up-regulated the expression of genes related to the cell-mediated cytotoxicity (CMC; tcrb and cd8a) and the interferon pathway (IFN; ifn, mx and ifng). In addition, 3 months after vaccination, challenged fish showed a retarded onset of fish death and lower cumulative mortality with a relative survival of 45%. Thus, we created a chitosan-encapsulated DNA vaccine against NNV that is partly protective to European sea bass juveniles and up-regulates the transcription of genes related to CMC and IFN. However, further studies are needed to improve the anti-NNV vaccine and to understand its mechanisms.

  3. CO/sub 2/ enrichment improves recovery of growth and photosynthesis from drought and nitrogen stress in maize

    International Nuclear Information System (INIS)

    In the context of the increasing risk of extreme drought as a result of climate change and increasing CO/sub 2/ in the future of northwest China, evaluation of crops ability to recover and survive droughts requires further attention. To test the effects of re-watering on plants suffering water and nitrogen limitations in the presence of elevated CO/sub 2/, maize (Zea mays) was planted to experience combined elevated CO/sub 2/ (380 or 750 micro mol/sup -1/, climate chamber), water stress (15% PEG-6000) and nitrogen limitation (5 or 15mM N in Hoagland solutions) and then re-watered at three levels (300mL, 600mL, 900mL per pot of distilled water). When plants were re-watered, drought stressed and N limited plants with ambient CO/sub 2/ increased their water content more than that of elevated CO/sub 2/, while the enhancement of growth rate were negatively related to the increasing plant water content. Elevated CO/sub 2/ could help re-watered seedlings to have higher photosynthetic capacity (Fv/Fm, PSII, Pn,Pn/Tr and Pn/Gs) and new leaf growth under low water content, apart from nitrogen deficiency. The results demonstrated that elevated CO2 could help drought stressed seedlings to maintain higher carbon assimilation rates under low water content, as a result to improve leaf water use efficiency. (author)

  4. Liposomes coated with N-trimethyl chitosan to improve the absorption of harmine in vivo and in vitro

    Directory of Open Access Journals (Sweden)

    Chen WL

    2016-01-01

    Full Text Available Wei-liang Chen,1,* Zhi-Qiang Yuan,1,* Yang Liu,1 Shu-di Yang,1 Chun-ge Zhang,1 Ji-zhao Li,1 Wen-jing Zhu,1 Fang Li,1 Xiao-feng Zhou,2,3 Yi-mei Lin,4 Xue-nong Zhang1 1Department of Pharmaceutics, College of Pharmaceutical Sciences, 2Department of Radiobiology, College of Radiological Medicine and Protection, Soochow University, Suzhou, 3Changshu Hospital of Traditional Chinese Medicine, Changshu, 4The Second Affiliated Hospital of Xinjiang Medical University, Urumqi, People’s Republic of China *These authors contributed equally to this work Abstract: In this study, harmine liposomes (HM-lip were prepared through the thin-film hydration–pH-gradient method and then coated with N-trimethyl chitosan (TMC. Particle size, zeta potential, entrapment efficiency, and in vitro release of HM-lip and TMC-coated harmine liposomes (TMC-HM-lip were also determined. Sprague Dawley rats were further used to investigate the pharmacokinetics in vivo. Retention behavior in mouse gastrointestinal tract (GIT was studied through high-performance liquid chromatography and near-infrared imaging. Degradation was further evaluated through incubation with Caco-2 cell homogenates, and a Caco-2 monolayer cell model was used to investigate the uptake and transport of drugs. HM-lip and TMC-HM-lip with particle size of 150–170 nm, an entrapment efficiency of about 81%, and a zeta potential of negative and positive, respectively, were prepared. The release of HM from HM-lip and TMC-HM-lip was slower than that from HM solution and was sensitive to pH. TMC-HM-lip exhibited higher oral bioavailability and had prolonged retention time in GIT. HM-lip and TMC-HM-lip could also protect HM against degradation in Caco-2 cell homogenates. The uptake amount of TMC-HM-lip was higher than that of HM and HM-lip. TMC-HM-lip further demonstrated higher apparent permeability coefficient (Papp from the apical to the basolateral side than HM and HM-lip because of its higher uptake and

  5. The role of maize root size in phosphorus uptake and productivity of maize/faba bean and maize/wheat intercropping systems.

    Science.gov (United States)

    Zhang, Yikai; Chen, Fanjun; Li, Long; Chen, Yanhua; Liu, Bingran; Zhou, Yuling; Yuan, Lixing; Zhang, Fusuo; Mi, Guohua

    2012-11-01

    Interspecific root/rhizosphere interactions affect phosphorus (P) uptake and the productivity of maize/faba bean and maize/wheat intercropping systems. The aim of these experiments was to determine whether manipulation of maize root growth could improve the productivity of the two intercropping systems. Two near isogenic maize hybrids (the larger-rooted T149 and smaller-rooted T222) were intercropped with faba bean and wheat, under conditions of high- and low-P availability. The larger-rooted T149 showed greater competitive ability than the smaller-rooted T222 in both maize/faba bean and maize/wheat intercropping systems. The higher competitive ability of T149 improved the productivity of the maize/faba bean intercropping system in P-sufficient conditions. In maize/wheat intercropping systems, root growth, shoot biomass, and P uptake of maize were inhibited by wheat, regardless of the P-supply. Compared with T222, the larger-rooted T149 suffered less in the intercropping systems. The total biomass of the maize/wheat intercropping system was higher for wheat/T149 than for wheat/T222 under low-P conditions. These data suggested that genetic improvement of maize root size could enhance maize growth and its ability to compete for P resources in maize/faba bean and maize/wheat intercropping systems. In addition, depending on the P availability, larger maize roots could increase the productivity of intercropping systems.

  6. Partitioning of simulated rainfall in a kaolinitic soil under improved fallow-maize rotation in Zimbabwe

    NARCIS (Netherlands)

    Nyamadzawo, G.; Nyamugafata, P.; Chikowo, R.; Giller, K.E.

    2003-01-01

    Research on improved fallows has concentrated on soil fertility benefits neglecting possible benefits to soil and water conservation. The effects of improved fallows on rainfall partitioning and associated soil loss were investigated using simulated rainfall on a kaolinitic soil in Zimbabwe. Simulat

  7. Engineering interfacial properties by anionic surfactant-chitosan complexes to improve stability of oil-in-water emulsions

    NARCIS (Netherlands)

    Zinoviadou, K.; Scholten, E.; Moschakis, T.; Biliaderis, C.G.

    2012-01-01

    Oil-in-water emulsions (10% w/w n-tetradecane) were prepared at pH = 5.7 by using, as surface active agents, electrostatically formed complexes of sodium stearoyl lactylate (SSL) at a concentration of 0.4% (w/w) and chitosan (CH) in a concentration range between 0 and 0.48% w/w. The use of complexes

  8. Antimicrobial Actions of Degraded and Native Chitosan against Spoilage Organisms in Laboratory Media and Foods

    OpenAIRE

    Rhoades, J.; Roller, S

    2000-01-01

    The objective of this study was to determine whether chitosan (poly-β-1,4-glucosamine) and hydrolysates of chitosan can be used as novel preservatives in foods. Chitosan was hydrolyzed by using oxidative-reductive degradation, crude papaya latex, and lysozyme. Mild hydrolysis of chitosan resulted in improved microbial inactivation in saline and greater inhibition of growth of several spoilage yeasts in laboratory media, but highly degraded products of chitosan exhibited no antimicrobial activ...

  9. Infiltration and planting pits for improved water management and maize yield in semi-arid Zimbabwe

    NARCIS (Netherlands)

    Nyakudya, I.W.; Stroosnijder, L.; Nyagumbo, I.

    2014-01-01

    Realising that rainwater harvesting (RWH) improves crop productivity, smallholder farmers in semi-arid Zimbabwe modified contour ridges traditionally used for rainwater management by digging infiltration pits inside contour ridge channels in order to retain more water in crop fields. However, scient

  10. Ensuring Improved Livelihood Opportunities for Resource-Poor Maize Farmers through the Dissemination of Striga Control Methods in Kwara State, Nigeria

    Directory of Open Access Journals (Sweden)

    OLORUNFEMI, O.D

    2014-06-01

    Full Text Available This paper examines the sources used by resource poor maize farmers in search of agricultural information on Striga control methods in Kwara State, Nigeria. A well structured interview schedule was used to elicit information using random sampling technique from one hundred and sixty (160 maize farmers in Edu and Patigi Local Government Areas which are highly endemic to Striga infestation in the State. Four sources of information were found effective in disseminating and diffusing Striga control methods in the area which include neighbours and friends, government agencies (ADP, agricultural extension agents and farmers groups. Logistic regression model of determinants of poverty revealed that characteristics of households that were more likely to be impoverished include small household size; low farm income, few years of farming experience and those whom Striga have been on their farms for long thereby having high yield loss to Striga. The study recommends an urgent need for extension agencies to intensify the use of the effective sources of information for disseminating Striga control methods to the farmers and it highlighted policies to improve the livelihoods of the resource-poor maize farmers in the Striga affected areas of Kwara State, Nigeria.

  11. Films, Buckypapers and Fibers from Clay, Chitosan and Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Marc in het Panhuis

    2011-04-01

    Full Text Available The mechanical and electrical characteristics of films, buckypapers and fiber materials from combinations of clay, carbon nanotubes (CNTs and chitosan are described. The rheological time-dependent characteristics of clay are maintained in clay–carbon nanotube–chitosan composite dispersions. It is demonstrated that the addition of chitosan improves their mechanical characteristics, but decreases electrical conductivity by three-orders of magnitude compared to clay–CNT materials. We show that the electrical response upon exposure to humid atmosphere is influenced by clay-chitosan interactions, i.e., the resistance of clay–CNT materials decreases, whereas that of clay–CNT–chitosan increases.

  12. Fabrication and characterization of nuclear localization signal-conjugated glycol chitosan micelles for improving the nuclear delivery of doxorubicin

    Directory of Open Access Journals (Sweden)

    Zhao J

    2012-09-01

    Full Text Available Jingmou Yu,1 Xin Xie,1 Meirong Zheng,1 Ling Yu,2 Lei Zhang,1 Jianguo Zhao,1 Dengzhao Jiang,1 Xiangxin Che11Key Laboratory of Systems Biology Medicine of Jiangxi Province, College of Basic Medical Science, Jiujiang University, Jiujiang, 2Division of Nursing, 2nd Affiliated Hospital, Yichun University, Yichun, People's Republic of ChinaBackground: Supramolecular micelles as drug-delivery vehicles are generally unable to enter the nucleus of nondividing cells. In the work reported here, nuclear localization signal (NLS-modified polymeric micelles were studied with the aim of improving nuclear drug delivery.Methods: In this research, cholesterol-modified glycol chitosan (CHGC was synthesized. NLS-conjugated CHGC (NCHGC was synthesized and characterized using proton nuclear magnetic resonance spectroscopy, dynamic light scattering, and fluorescence spectroscopy. Doxorubicin (DOX, an anticancer drug with an intracellular site of action in the nucleus, was chosen as a model drug. DOX-loaded micelles were prepared by an emulsion/solvent evaporation method. The cellular uptake of different DOX formulations was analyzed by flow cytometry and confocal laser scanning microscopy. The cytotoxicity of blank micelles, free DOX, and DOX-loaded micelles in vitro was investigated by 3-(4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide (MTT assay in HeLa and HepG2 cells.Results: The degree of substitution was 5.9 cholesterol and 3.8 NLS groups per 100 sugar residues of the NCHGC conjugate. The critical aggregation concentration of the NCHGC micelles in aqueous solution was 0.0209 mg/mL. The DOX-loaded NCHGC (DNCHGC micelles were observed as being almost spherical in shape under transmission electron microscopy, and the size was determined as 248 nm by dynamic light scattering. The DOX-loading content of the DNCHGC micelles was 10.1%. The DOX-loaded micelles showed slow drug-release behavior within 72 hours in vitro. The DNCHGC micelles exhibited greater

  13. N-trimethyl chitosan (TMC)-modified microemulsions for improved oral bioavailability of puerarin: preparation and evaluation.

    Science.gov (United States)

    Liao, Dehua; Liu, Xinyi; Dai, Wei; Tang, Tiantian; Ou, Ge; Zhang, Kai; Han, Meng; Kang, Rongrong; Yang, Sufang; Xiang, Daxiong

    2015-01-01

    The aim of this research was to increase the oral bioavailability of puerarin by N-trimethyl chitosan-modified microemulsions (TMC-MEs) loaded with puerarin. Different concentrations of TMC-modified microemulsions were prepared in our study, and then evaluated for particle size, zeta potential, morphological observation and changes of the microenvironment polarity of inner oil core. It was shown that the zeta potential of the microemulsion was increased with the increasing concentration of TMC, and the peak value was achieved when the concentration of TMC was 3.0 mg/mL. The enhancement of the ratio of I(1)/I(3) (the ratio between the first band and the third band of the emission fluorescence spectrum of pyrene, I(1) = 373 nm, I(3) = 384 nm) indicated that polarity of the inner core of TMC-MEs was increased with the addition of the modifier. Pharmacokinetic studies demonstrated that after oral administration of puerarin N-trimethyl chitosan (TMC)-modified microemulsions (PUE-TMEs) and puerarin microemulsions (PUE-MEs) to rats at a dose of 100 mg/kg, relative bioavailability was enhanced about 6.8- and 1.2-fold, respectively, compared to puerarin suspension (PUE-SUS) as control. It indicated that the TMC-MEs could be used as an effective formulation for enhancing the oral bioavailability of puerarin. PMID:24467620

  14. Nanoparticle mediated P-glycoprotein silencing for improved drug delivery across the blood-brain barrier: a siRNA-chitosan approach.

    Directory of Open Access Journals (Sweden)

    Jostein Malmo

    Full Text Available The blood-brain barrier (BBB, composed of tightly organized endothelial cells, limits the availability of drugs to therapeutic targets in the central nervous system. The barrier is maintained by membrane bound efflux pumps efficiently transporting specific xenobiotics back into the blood. The efflux pump P-glycoprotein (P-gp, expressed at high levels in brain endothelial cells, has several drug substrates. Consequently, siRNA mediated silencing of the P-gp gene is one possible strategy how to improve the delivery of drugs to the brain. Herein, we investigated the potential of siRNA-chitosan nanoparticles in silencing P-gp in a BBB model. We show that the transfection of rat brain endothelial cells mediated effective knockdown of P-gp with subsequent decrease in P-gp substrate efflux. This resulted in increased cellular delivery and efficacy of the model drug doxorubicin.

  15. Suppression of Zn stress on barley by irradiated chitosan

    Energy Technology Data Exchange (ETDEWEB)

    Nagasawa, N.; Mitomo, H. [Gunma Univ., Faculty of Engineering, Department of Biological and Chemical Engineering, Kiryu, Gunma (Japan); Ha, P.T.L. [Nuclear Research Institute, Dalat (Viet Nam); Watanabe, S.; Ito, T.; Takeshita, H.; Yoshii, F.; Kume, T. [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    2001-03-01

    Chitosan was irradiated up to 1000 kGy in solid state. Irradiation of chitosan caused the reduction of molecular weight. The molecular weight of the chitosan reduced from ca. 4 x 10{sup 5} to ca. 6 x 10{sup 3} by irradiation at 1000 kGy. For the barley growth promotion, irradiated chitosan showed the significant effect and 1000 kGy irradiated chitosan improved 20% of growth. Using the positron emitting tracer imaging system (PETIS), the effect of chitosan on uptake and transportation of {sup 62}Zn in barley were investigated. It was found that the transportation of Zn from root to shoot and the damage of plant by Zn were suppressed with irradiated chitosan. (author)

  16. Suppression of Zn stress on barley by irradiated chitosan

    International Nuclear Information System (INIS)

    Chitosan was irradiated up to 1000 kGy in solid state. Irradiation of chitosan caused the reduction of molecular weight. The molecular weight of the chitosan reduced from ca. 4 x 105 to ca. 6 x 103 by irradiation at 1000 kGy. For the barley growth promotion, irradiated chitosan showed the significant effect and 1000 kGy irradiated chitosan improved 20% of growth. Using the positron emitting tracer imaging system (PETIS), the effect of chitosan on uptake and transportation of 62Zn in barley were investigated. It was found that the transportation of Zn from root to shoot and the damage of plant by Zn were suppressed with irradiated chitosan. (author)

  17. Chitosan in Mucoadhesive Drug Delivery: Focus on Local Vaginal Therapy

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    Toril Andersen

    2015-01-01

    Full Text Available Mucoadhesive drug therapy destined for localized drug treatment is gaining increasing importance in today’s drug development. Chitosan, due to its known biodegradability, bioadhesiveness and excellent safety profile offers means to improve mucosal drug therapy. We have used chitosan as mucoadhesive polymer to develop liposomes able to ensure prolonged residence time at vaginal site. Two types of mucoadhesive liposomes, namely the chitosan-coated liposomes and chitosan-containing liposomes, where chitosan is both embedded and surface-available, were made of soy phosphatidylcholine with entrapped fluorescence markers of two molecular weights, FITC-dextran 4000 and 20,000, respectively. Both liposomal types were characterized for their size distribution, zeta potential, entrapment efficiency and the in vitro release profile, and compared to plain liposomes. The proof of chitosan being both surface-available as well as embedded into the liposomes in the chitosan-containing liposomes was found. The capability of the surface-available chitosan to interact with the model porcine mucin was confirmed for both chitosan-containing and chitosan-coated liposomes implying potential mucoadhesive behavior. Chitosan-containing liposomes were shown to be superior in respect to the simplicity of preparation, FITC-dextran load, mucoadhesiveness and in vitro release and are expected to ensure prolonged residence time on the vaginal mucosa providing localized sustained release of entrapped model substances.

  18. Selenium Supplementation Affects Physiological and Biochemical Processes to Improve Fodder Yield and Quality of Maize (Zea mays L.) under Water Deficit Conditions

    Science.gov (United States)

    Nawaz, Fahim; Naeem, Muhammad; Ashraf, Muhammad Y.; Tahir, Muhammad N.; Zulfiqar, Bilal; Salahuddin, Muhammad; Shabbir, Rana N.; Aslam, Muhammad

    2016-01-01

    Climate change is one of the most complex challenges that pose serious threats to livelihoods of poor people who rely heavily on agriculture and livestock particularly in climate-sensitive developing countries of the world. The negative effects of water scarcity, due to climate change, are not limited to productivity food crops but have far-reaching consequences on livestock feed production systems. Selenium (Se) is considered essential for animal health and has also been reported to counteract various abiotic stresses in plants, however, understanding of Se regulated mechanisms for improving nutritional status of fodder crops remains elusive. We report the effects of exogenous selenium supply on physiological and biochemical processes that may influence green fodder yield and quality of maize (Zea mays L.) under drought stress conditions. The plants were grown in lysimeter tanks under natural conditions and were subjected to normal (100% field capacity) and water stress (60% field capacity) conditions. Foliar spray of Se was carried out before the start of tasseling stage (65 days after sowing) and was repeated after 1 week, whereas, water spray was used as a control. Drought stress markedly reduced the water status, pigments and green fodder yield and resulted in low forage quality in water stressed maize plants. Nevertheless, exogenous Se application at 40 mg L-1 resulted in less negative leaf water potential (41%) and enhanced relative water contents (30%), total chlorophyll (53%), carotenoid contents (60%), accumulation of total free amino acids (40%) and activities of superoxide dismutase (53%), catalase (30%), peroxidase (27%), and ascorbate peroxidase (27%) with respect to control under water deficit conditions. Consequently, Se regulated processes improved fodder yield (15%) and increased crude protein (47%), fiber (10%), nitrogen free extract (10%) and Se content (36%) but did not affect crude ash content in water stressed maize plants. We propose that Se

  19. Improvement of intestinal absorption of forsythoside A and chlorogenic acid by different carboxymethyl chitosan and chito-oligosaccharide, application to Flos Lonicerae-Fructus Forsythiae herb couple preparations.

    Directory of Open Access Journals (Sweden)

    Wei Zhou

    Full Text Available The current study aims to investigate the effect of chitosan derivatives on the intestinal absorption and bioavailabilities of forsythoside A (FTA and Chlorogenic acid (CHA, the major active components in Flos Lonicerae-Fructus Forsythiae herb couple. Biopharmaceutics and pharmacokinetics properties of the two compounds have been characterized in vitro, in situ as well as in rats. Based on the identified biopharmaceutics characteristics of the two compounds, the effect of chitosan derivatives as an absorption enhancer on the intestinal absorption and pharmacokinetics of FTA and CHA in pure compound form as well as extract form were investigated in vitro, in situ and in vivo. Both FTA and CHA demonstrated very limited intestinal permeabilities, leading to oral bioavailabilities being only 0.50% and 0.13% in rats, respectively. Results from both in vitro, in situ as well as in vivo studies consistently indicated that Chito-oligosaccharide (COS at dosage of 25 mg/kg could enhance intestinal permeabilities significantly as well as the in vivo bioavailabilities of both FTA and CHA than CMCs in Flos Lonicerae-Fructus Forsythiae herb couple preparations, and was safe for gastrointestine from morphological observation. Besides, treatment with Flos Lonicerae-Fructus Forsythiae herb couple preparations with COS at the dosage of 25 mg/kg prevented MDCK damage after influenza virus propagation, which was significantly better than control. The current findings not only identified the usefulness of COS for the improved delivery of Flos Lonicerae-Fructus Forsythiae preparations but also demonstrated the importance of biopharmaceutical characterization in the dosage form development of traditional Chinese medicine.

  20. Degradation and compatibility behaviors of poly(glycolic acid) grafted chitosan.

    Science.gov (United States)

    Zhang, Luzhong; Dou, Sufeng; Li, Yan; Yuan, Ying; Ji, Yawei; Wang, Yaling; Yang, Yumin

    2013-07-01

    The films of poly(glycolic acid) grafted chitosan were prepared without using a catalyst to improve the degradable property of chitosan. The films were characterized by Fourier transform-infrared spectroscopy and X-ray photoelectron spectroscopy (XPS). The degradation of the poly(glycolic acid) grafted chitosan films were investigated in the lysozyme solution. In vitro degradation tests revealed that the degradation rate of poly(glycolic acid) grafted chitosan films increased dramatically compared with chitosan. The degradation rate of poly(glycolic acid) grafted chitosan films gradually increased with the increasing of the molar ratio of glycolic acid to chitosan. Additionally, the poly(glycolic acid) grafted chitosan films have good biocompatibility, as demonstrated by in vitro cytotoxicity of the extraction fluids. The biocompatible and biodegradable poly(glycolic acid) grafted chitosan would be an effective material with controllable degradation rate to meet the diverse needs in biomedical fields.

  1. In-Season Root-Zone Nitrogen Management Strategies for Improving Nitrogen Use Efficiency in High-Yielding Maize Production in China

    Institute of Scientific and Technical Information of China (English)

    MENG Qing-Feng; CHEN Xin-Ping; ZHANG Fu-Suo; CAO Ming-Hui; CUI Zhen-Ling; BAI Jin-Shun; YUE Shan-Chao; CHEN Su-Yi; T.M(U)LLER

    2012-01-01

    Many recently developed N management strategies have been extremely successful in improving N use efficiency.However,attempts to further increase grain yields have had limited success.Field experiments were conducted in 2007 and 2008 at four sites to evaluate the effect of an in-season root-zone N management strategy on maize (Zea mays L.).According to the in-season root-zone N management,the optimal N rate (ONR) was determined by subtracting measured soil mineral N (NH4+-N and NO3--N) in the root zone from N target values.Other treatments included a control without N fertilization,70% of ONR,130% of ONR,and recommended N rate (RNR) by agronomists in China that have been shown to approach maize yield potentials.Although apparent N recovery for the ONR treatment was significantly higher than that under RNR in 2007,grain yield declined from 13.3 to 11.0 Mg ha-1 because of an underestimation of N uptake.In 2008,N target values were adjusted to match crop uptake,and N fertilization rates were reduced from 450 kg N ha- 1 for RNR to 225 to 265 kg N ha-1 for ONR.High maize yields were maintained at 12.6 to 13.5 Mg ha-1,which were twice the yield from typical farmers'practice.As a result,apparent N recovery increased from 29% to 66%,and estimated N losses decreased significantly for the ONR treatment compared to the RNR treatment.In conclusion,the in-season root-zone N management approach was able to achieve high yields,high NUE and low N losses.

  2. 壳聚糖护肤液促进大鼠伤口愈合的研究%Chitosan liquid improves wound healing in rats

    Institute of Scientific and Technical Information of China (English)

    杨虎; 郑丽君; 黄新建; 张梦媛; 谈伟强

    2011-01-01

    目的 探讨壳聚糖护肤液促进伤口愈合的作用.方法 在大鼠背部伤口模型上用药,对壳聚糖护肤液组(A组)、碱性成纤维细胞生长因子组(B组)、生理氯化钠溶液组(C组)进行两两对照,肉眼观察伤口愈合时间,并于伤后3、7、14d,取皮肤修复组织行光镜观察.结果 A组愈合时间为(17.3±1.35)d,B组为(18.2±1.15)d,C组为(24.0±1.37)d.A组与B组的愈合时间差异无统计学意义(P>0.05),A组、B组与C组的愈合时间差异有统计学意义(P<0.05);壳聚糖护肤液在伤口愈合的早期促进毛细血管芽和血管内皮细胞生成,中期促进成纤维细胞和胶原纤维生成,后期使胶原纤维排列有序.结论 壳聚糖护肤液具有较好的促进伤口愈合的作用.%Objective To study the promotive effect of chitosan liquid on wound healing.Methods Wound model was established on the back of 60 rats,which were classified into 3 groups to be treated with topical chitosan liquid (group A),basic fibroblast growth factor (group B),and sodium chloride physiological solution (group C),respectively.The time required for the healing of wound was recorded.Regenerated tissues were resected from the rats on day 3,7 and 14 after the establishment of wound model,and observed with light microscopy.Results The time required for the healing of wound was 17.3 ± 1.35 days in group A,18.2 ± 1.15 days in group B,and 24.0 ± 1.37 days in group C.For the time required for the healing of wound,no significant difference was observed between the group A and B (P > 0.05),but group C significantly differed from group A and B (both P < 0.05).Chitosan liquid accelerated the generation of capillary sprouts and vascular endothelial cells at the early stage of wound healing,promoted the production of fibroblasts and collagen fibers at the middle stage,and improved the organization of collagen fibers at the late stage.Conclusion Chitosan liquid exerts a promising promotive effect on wound

  3. Environmental applications of chitosan and its derivatives.

    Science.gov (United States)

    Yong, Soon Kong; Shrivastava, Manoj; Srivastava, Prashant; Kunhikrishnan, Anitha; Bolan, Nanthi

    2015-01-01

    Chitosan originates from the seafood processing industry and is one of the most abundant of bio-waste materials. Chitosan is a by-product of the alkaline deacetylation process of chitin. Chemically, chitosan is a polysaccharide that is soluble in acidic solution and precipitates at higher pHs. It has great potential for certain environmental applications, such as remediation of organic and inorganic contaminants, including toxic metals and dyes in soil, sediment and water, and development of contaminant sensors. Traditionally, seafood waste has been the primary source of chitin. More recently, alternative sources have emerged such as fungal mycelium, mushroom and krill wastes, and these new sources of chitin and chitosan may overcome seasonal supply limitations that have existed. The production of chitosan from the above-mentioned waste streams not only reduces waste volume, but alleviates pressure on landfills to which the waste would otherwise go. Chitosan production involves four major steps, viz., deproteination, demineralization, bleaching and deacetylation. These four processes require excessive usage of strong alkali at different stages, and drives chitosan's production cost up, potentially making the application of high-grade chitosan for commercial remediation untenable. Alternate chitosan processing techniques, such as microbial or enzymatic processes, may become more cost-effective due to lower energy consumption and waste generation. Chitosan has proved to be versatile for so many environmental applications, because it possesses certain key functional groups, including - OH and -NH2 . However, the efficacy of chitosan is diminished at low pH because of its increased solubility and instability. These deficiencies can be overcome by modifying chitosan's structure via crosslinking. Such modification not only enhances the structural stability of chitosan under low pH conditions, but also improves its physicochemical characteristics, such as porosity

  4. Application of bokashi and sunn hemp (Crotalaria juncea L. to improve inorganic fertilizer efficiency on maize (Zea mays L.

    Directory of Open Access Journals (Sweden)

    A.I. Yuliana

    2015-10-01

    Full Text Available A field experiment was conducted lo learn about the effect of Bokashi and Sunn hemp (Crotalaria juncea L. on maize production and inorganic fertilizer use efficiency on maize. The experiment was conducted in Jatikerto, Malang; at the altitude of 303 m above sea level, in Alfisol soil type, the average daily temperature ranges 21-33oC, from June to October 2013. The experiment was conducted as factorial, designed in a randomized block design (RBD. The first factor was dose of inorganic fertilizer (100% ; 75% and 50% of recommendation dose. The second factor was the organic fertilizer (Without organic fertilizer20 t Bokashi/ ha, 20 t Sunn hemp/ha, 10 t Bokashi/ha + 10 t Sunn hemp/ha. The results showed that application of 20 t Bokashi/ha, 20 t Sunn hemp/ha, and combination of 10 t Bokashi/ha + 10 t Sunn hemp/ha, along with the application of inorganic fertilizer by dose of 100% increased the yields of maize for about 41.8%; 47.6% and 54.7% (10.73 t/ha; 11.17 t/ha, and 11.71 t/ha, respectively. The yield and nutrient use efficiency in the treatment dose of 100% inorganic fertilizer did not have any significant difference from the application of 20 t Bokashi /ha, 20 t Sunn hemp/ha, and 10 t Bokashi/ha + 10 t Sunn hemp/ha along with doses of inorganic fertilization 75% and 50%. Therefore, the organic fertilizer of 20 t Bokashi/ ha, 20 t Sunn hemp/ha, and combination of 10 t Bokashi/ha + 10 t Sunn hemp/ha could reduce the need of inorganic fertilizer for about 50%.

  5. Encapsulation in alginate and alginate coated-chitosan improved the survival of newly probiotic in oxgall and gastric juice.

    Science.gov (United States)

    Trabelsi, Imen; Bejar, Wacim; Ayadi, Dorra; Chouayekh, Hichem; Kammoun, Radhouane; Bejar, Samir; Ben Salah, Riadh

    2013-10-01

    This study was undertaken to develop an optimum composition model for the microencapsulation of a newly probiotic on sodium alginate using response surface methodology. The individual and interactive effects of three independent variables, namely sodium alginate concentration, biomass concentration, and hardening time, were investigated using Box-Behnken design experiments. A second ordered polynomial model was fitted and optimum conditions were estimated. The optimal conditions identified were 2% for sodium alginate, 10(10)UFC/ml for biomass, and 30 min for hardening time. The experimental value obtained for immobilized cells under these conditions was about 80.98%, which was in close agreement with the predicted value of 82.6%. Viability of microspheres (96%) was enhanced with chitosan as coating materials. The survival rates of free and microencapsulated Lactobacillus plantarum TN8 during exposure to artificial gastrointestinal conditions were compared. The results revealed that the encapsulated cells exhibited significantly higher resistances to artificial intestinal juice (AIJ) and artificial gastric juice (AGJ). Microencapsulation was also noted to effectively protect the strain from heating at 65 °C and refrigerating at 4 °C. Taken together, the findings indicated that microencapsulation conferred important protective effects to L. plantarum against the gastrointestinal conditions encountered during the transit of food.

  6. Formulation of insulin-loaded N-trimethyl chitosan microparticles with improved efficacy for inhalation by supercritical fluid assisted atomization.

    Science.gov (United States)

    Shen, Yu-Bin; Du, Zhe; Tang, Chuan; Guan, Yi-Xin; Yao, Shan-Jing

    2016-05-30

    Supercritical fluid assisted atomization introduced by a hydrodynamic cavitation mixer (SAA-HCM) was proposed as a green technique to fabricate insulin-loaded dry powders for inhalation administration. N-trimethyl chitosan (TMC), a polymeric mucoadhesive absorption enhancer, was synthesized and successfully micronized from aqueous solution using SAA-HCM. The prepared well-defined spherical TMC microparticles with preserved structure and thermal stability were potential carriers for delivery of proteins. Then, insulin-loaded TMC microparticles with high loading efficiency were coprecipitated from aqueous solutions using SAA-HCM without use of any organic solvents. The polymer/protein ratio revealed to be a factor influencing the particle morphology, and non-coalescing composite microparticles in amorphous state mainly ranging from 1μm to 5μm could be obtained in this work. Aerodynamic properties were assessed by next generation impactor (NGI) and the mass median aerodynamic diameter (MMAD) lied inside the inhalable range of 1-5μm, while fine particle fraction (FPF) reached above 60%. The structural integrity of encapsulated insulin was confirmed by HPLC, circular dichroism and fluorescence spectroscopy. In vivo study demonstrated that TMC could enhance the absorption and bioavailability of the pulmonarily administered insulin formulation for SD rats. These results suggest that TMC microparticles could be efficiently prepared as a promising vehicle for drug delivery, and SAA-HCM is a promising technique to prepare inhalable polymer/protein composite dry powders. PMID:27034000

  7. Films, Buckypapers and Fibers from Clay, Chitosan and Carbon Nanotubes

    OpenAIRE

    Marc in het Panhuis; Holly Warren; Higgins, Thomas M.

    2011-01-01

    The mechanical and electrical characteristics of films, buckypapers and fiber materials from combinations of clay, carbon nanotubes (CNTs) and chitosan are described. The rheological time-dependent characteristics of clay are maintained in clay–carbon nanotube–chitosan composite dispersions. It is demonstrated that the addition of chitosan improves their mechanical characteristics, but decreases electrical conductivity by three-orders of magnitude compared to clay–CNT materials. We show that ...

  8. Contribution to the improvement of a porridge made with fermented maize: effect of selected foods and lemon on energy density, pH, viscosity and nutritional quality.

    Science.gov (United States)

    Ejigui, Jeanne; Desrosiers, Therese

    2011-08-01

    The objective of the present study was to use lemon and selected foods to improve the nutritional characteristics, quality and the nutrient content of a traditional complementary porridge made of lactic acid fermented yellow maize. Boiled egg yolk, roasted peanut paste, dry crayfish flour, roasted soybean flour and lemon juice were used as food additions. Amounts of food added were calculated on the basis of World Health Organization estimated energy needs from complementary foods of well-nourished children in developing countries, aged 9-11 months, at four servings per day and a low amount of breast milk energy. The pH and viscosity increased in porridges with food addition, but lemon juice contributed to lowering them. Energy and nutrient densities/100 g porridge improved with food addition regardless of the use of lemon juice. An increase in iron, zinc and calcium in vitro availability was observed (P < 0.05) with the addition of lemon juice.

  9. Aqueous Behaviour of Chitosan

    Directory of Open Access Journals (Sweden)

    D. P. Chattopadhyay

    2010-01-01

    Full Text Available Chitosan, a versatile biopolymer, finds numerous applications in textile processing unit operations such as preparation, dyeing, printing, and finishing. However, the accessibility of this biopolymer by the textile material depends on the viscosity of its solution which in turn is a function of its molecular weight. In this work, therefore, the effect of molecular weight, storage life, presence of electrolyte, and particle size of chitosan on its viscosity was investigated. Chitosan of different molecular weights was synthesized by nitrous acid hydrolysis of parent chitosan solution. The synthesized low molecular weight products were analysed by FTIR spectroscopy. Chitosan of nanoconfiguration was prepared by Ionotropic gelation method and characterized by particle size analyzer. The viscosity of different chitosan solutions was determined using Ubbelohde capillary viscometer. As an extension to this study, the chelation property of chitosan was also evaluated.

  10. Chitosan and radiation chemistry

    Science.gov (United States)

    Chmielewski, Andrzej G.

    2010-03-01

    Chitosan as a raw material with special properties has drawn attention of scientists working in the field of radiation processing and natural polymer products development, and also of specialists working in the field of radiation protection and oncologists. Especially the applications concern reduced molecular weight chitosan which still retain its chemical structure; such form of the compound is fostering biological, physical and chemical reactivity of the product. Chitosan degrades into fragments under γ-ray or electron beam irradiation. Antibacterial properties of the product are applied in manufacturing hydrogel for wound dressing and additional healing properties can be achieved by incorporating in the hydrogel matrix chitosan bonded silver clusters. Another possible application of chitosan is in reducing radiation damage to the radiation workers or radiation cured patients. In the case of radioisotopes oral or respiratory chitosan-based materials can be applied as chelators. Applications of chitosan in oncology are also reported.

  11. Chitosan and radiation chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Chmielewski, Andrzej G., E-mail: a.chmielewski@ichtj.waw.p [Institute of Nuclear Chemistry and Technology, Warsaw (Poland)

    2010-03-15

    Chitosan as a raw material with special properties has drawn attention of scientists working in the field of radiation processing and natural polymer products development, and also of specialists working in the field of radiation protection and oncologists. Especially the applications concern reduced molecular weight chitosan which still retain its chemical structure; such form of the compound is fostering biological, physical and chemical reactivity of the product. Chitosan degrades into fragments under gamma-ray or electron beam irradiation. Antibacterial properties of the product are applied in manufacturing hydrogel for wound dressing and additional healing properties can be achieved by incorporating in the hydrogel matrix chitosan bonded silver clusters. Another possible application of chitosan is in reducing radiation damage to the radiation workers or radiation cured patients. In the case of radioisotopes oral or respiratory chitosan-based materials can be applied as chelators. Applications of chitosan in oncology are also reported.

  12. Chitosan and radiation chemistry

    International Nuclear Information System (INIS)

    Chitosan as a raw material with special properties has drawn attention of scientists working in the field of radiation processing and natural polymer products development, and also of specialists working in the field of radiation protection and oncologists. Especially the applications concern reduced molecular weight chitosan which still retain its chemical structure; such form of the compound is fostering biological, physical and chemical reactivity of the product. Chitosan degrades into fragments under γ-ray or electron beam irradiation. Antibacterial properties of the product are applied in manufacturing hydrogel for wound dressing and additional healing properties can be achieved by incorporating in the hydrogel matrix chitosan bonded silver clusters. Another possible application of chitosan is in reducing radiation damage to the radiation workers or radiation cured patients. In the case of radioisotopes oral or respiratory chitosan-based materials can be applied as chelators. Applications of chitosan in oncology are also reported.

  13. Recent advances in chitosan-based nanoparticulate pulmonary drug delivery

    Science.gov (United States)

    Islam, Nazrul; Ferro, Vito

    2016-07-01

    The advent of biodegradable polymer-encapsulated drug nanoparticles has made the pulmonary route of administration an exciting area of drug delivery research. Chitosan, a natural biodegradable and biocompatible polysaccharide has received enormous attention as a carrier for drug delivery. Recently, nanoparticles of chitosan (CS) and its synthetic derivatives have been investigated for the encapsulation and delivery of many drugs with improved targeting and controlled release. Herein, recent advances in the preparation and use of micro-/nanoparticles of chitosan and its derivatives for pulmonary delivery of various therapeutic agents (drugs, genes, vaccines) are reviewed. Although chitosan has wide applications in terms of formulations and routes of drug delivery, this review is focused on pulmonary delivery of drug-encapsulated nanoparticles of chitosan and its derivatives. In addition, the controversial toxicological effects of chitosan nanoparticles for lung delivery will also be discussed.

  14. Recent advances in chitosan-based nanoparticulate pulmonary drug delivery.

    Science.gov (United States)

    Islam, Nazrul; Ferro, Vito

    2016-08-14

    The advent of biodegradable polymer-encapsulated drug nanoparticles has made the pulmonary route of administration an exciting area of drug delivery research. Chitosan, a natural biodegradable and biocompatible polysaccharide has received enormous attention as a carrier for drug delivery. Recently, nanoparticles of chitosan (CS) and its synthetic derivatives have been investigated for the encapsulation and delivery of many drugs with improved targeting and controlled release. Herein, recent advances in the preparation and use of micro-/nanoparticles of chitosan and its derivatives for pulmonary delivery of various therapeutic agents (drugs, genes, vaccines) are reviewed. Although chitosan has wide applications in terms of formulations and routes of drug delivery, this review is focused on pulmonary delivery of drug-encapsulated nanoparticles of chitosan and its derivatives. In addition, the controversial toxicological effects of chitosan nanoparticles for lung delivery will also be discussed. PMID:27439116

  15. Improvement of Intestinal Absorption of Forsythoside A and Chlorogenic Acid by Different Carboxymethyl Chitosan and Chito-oligosaccharide, Application to Flos Lonicerae - Fructus Forsythiae Herb Couple Preparations

    OpenAIRE

    Wei Zhou; Haidan Wang; Xuanxuan Zhu; Jinjun Shan; Ailing Yin; Baochang Cai; Liuqing Di

    2013-01-01

    The current study aims to investigate the effect of chitosan derivatives on the intestinal absorption and bioavailabilities of forsythoside A (FTA) and Chlorogenic acid (CHA), the major active components in Flos Lonicerae - Fructus Forsythiae herb couple. Biopharmaceutics and pharmacokinetics properties of the two compounds have been characterized in vitro, in situ as well as in rats. Based on the identified biopharmaceutics characteristics of the two compounds, the effect of chitosan derivat...

  16. Research of the Mechanism of Enhancing Biological Treatment by Chitosan

    Institute of Scientific and Technical Information of China (English)

    CHEN Liang; QIN Bing; CHEN Dong-hui

    2006-01-01

    Chitosan of different molecular weight (M. W. ) was added into SBR bioreactor to treat domestic wastewater. From comparison of treatment efficiency, sludge activity, sludge structure etc., we revealed the mechanism that chitosan enhanced the biological treatment function of activated sludge. The results proved that, chitosan is certain to restrain the reaction of activated sludge, but it do improve the structure of sludge fiocs and increase the treatment efficiency of activated sludge. The bigger the M. W. of chitosan is, the better the efficiency of enhancing biological treatment can be.

  17. Processing and characterization of 3D dense chitosan pieces, for orthopedic applications, by adding plasticizers

    OpenAIRE

    Figueiredo, Lígia; Moura, Carla; Pinto, Luís F. V.; Ferreira, Frederico Castelo; Rodrigues, Alexandra

    2015-01-01

    In this work, plasticizer agents were incorporated in a chitosan based formulation, as a strategy to improve the fragile structure of chitosan based-materials. Three different plasticizers: ethylene glycol, glycerol and sorbitol, were blended with chitosan to prepare 3D dense chitosan specimens. The properties of the obtained structures were assessed for mechanical, microstructural, physical and biocompatibility behavior. The results obtained revealed that from the different specimens prepare...

  18. Synthesis of Conjugated Chitosan and its Effect on Drug Permeation from Transdermal Patches

    OpenAIRE

    B K Satheeshababu; K L Shivakumar

    2013-01-01

    The aim of this study was to synthesis the conjugated chitosan by covalent attachment of thiol moieties to the cationic polymer, mediated by a carbodiimide to improve permeation properties of chitosan. Thioglycolic acid was covalently attached to chitosan by the formation of amide bonds between the primary amino groups of the polymer and the carboxylic acid groups of thioglycolic acid. Hence, these polymers are called as thiomers or thiolated polymers. Conjugation of chitosan was confirmed by...

  19. Chitosan-tripolyphosphate nanoparticles: Optimization of formulation parameters for improving process yield at a novel pH using artificial neural networks.

    Science.gov (United States)

    Hashad, Rania A; Ishak, Rania A H; Fahmy, Sherif; Mansour, Samar; Geneidi, Ahmed S

    2016-05-01

    At a novel pH value of the polymeric solution (6.2), variable chitosan (Cs) and sodium tripolyphosphate (TPP) concentrations and mass ratios were optimized to improve the process yield without undesirable particle flocculation. Prepared formulations were characterized in terms of particle size (PS), zeta potential (ZP) and percentage yield (% yield). Artificial neural networks (ANN) were built up and used to identify the parameters that control nanoparticle (NP) size and yield, in addition to being tested for their ability to predict these two experimental outputs. Using these networks, it was found that TPP concentration has the greatest effect on PS and% yield. The most optimum formulation was characterized by a notable process yield reaching 91.5%, a mean hydrodynamic PS 227 nm, ZP+24.13 mv and spherical compact morphology. Successful Cs-TPP interaction in NP formation was confirmed by both Fourier transform-infrared spectroscopy (FT-IR) and differential scanning calorimetry (DSC). This study demonstrated the ability of ANN to predict not only PS of the formed particles but also NP% yield. This may have a great impact on Cs-TPP NPs preparation and can be used to customize the required target formulations. PMID:26783636

  20. Glassy carbon electrode modified with gold nanoparticles and hemoglobin in a chitosan matrix for improved pH-switchable sensing of hydrogen peroxide

    International Nuclear Information System (INIS)

    Hemoglobin (Hb) has been demonstrated to endow electrochemical sensors with pH-switchable response because of the presence of carboxyl and amino groups. Hb was deposited in a chitosan matrix on a glassy carbon electrode (GCE) that was previously coated with clustered gold nanoparticles (Au-NPs) by electrodeposition. The switching behavior is active (“on”) to the negatively charged probe [Fe(CN)63−] at pH 4.0, but inactive (“off”) to the probe at pH 8.0. This switch is fully reversible by simply changing the pH value of the solution and can be applied for pH-controlled reversible electrochemical reduction of H2O2 catalyzed by Hb. The modified electrode was tested for its response to the different electroactive probes. The response to these species strongly depends on pH which was cycled between 4 and 8. The effect is also attributed to the presence of pH dependent charges on the surface of the electrode which resulted in either electrostatic attraction or repulsion of the electroactive probes. The presence of Hb, in turn, enhances the pH-controllable response, and the electrodeposited Au-NPs improve the capability of switching. This study reveals the potential of protein based pH-switchable materials and also provides a simple and effective strategy for fabrication of switchable chemical sensors as exemplified in a pH-controllable electrode for hydrogen peroxide. (author)

  1. Physical stability and moisture sorption of aqueous chitosan-amylose starch films plasticized with polyols

    DEFF Research Database (Denmark)

    Cervera, Mirna Fernández; Karjalainen, Milja; Airaksinen, Sari;

    2004-01-01

    The short-term stability and the water sorption of films prepared from binary mixtures of chitosan and native amylose maize starch (Hylon VII) were evaluated using free films. The aqueous polymer solutions of the free films contained 2% (w/w) film formers, glycerol, or erythritol as a plasticizer...

  2. Modification of chitosan with monomethyl fumaric acid in an ionic liquid solution.

    Science.gov (United States)

    Wang, Zhaodong; Zheng, Liuchun; Li, Chuncheng; Zhang, Dong; Xiao, Yaonan; Guan, Guohu; Zhu, Wenxiang

    2015-03-01

    Antibacterial and antioxidant monomethyl fumaric acid (MFA) was selected to modify chitosan, using aqueous solution of an ionic liquid as a homogeneous and green reaction media. The chemical structures of resulting polymers were systematically characterized by (1)H NMR, diffusion ordered spectroscopy, solid (13)C NMR and wide-angle X-ray diffraction. The results show that two kinds of MFA modified chitosan materials with totally different chemical structures have been synthesized. One product was a MF-chitosan salt composed of chitosan cation and MFA anion, which was obtained with the mediation of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) and N-hydroxysuccinimide. The other one synthesized with the mediation of EDC was a MF-chitosan amide in which MFA and chitosan are covalently attached. Solubility of chitosan has been improved, and MF-chitosan salt can be readily dissolved in water. The antioxidant activity has been enhanced with the introduction of MFA, irrespective of the chemical structure.

  3. Biophysical studies on chitosan-coated liposomes.

    Science.gov (United States)

    Mady, Mohsen M; Darwish, Mirhane M; Khalil, Safaa; Khalil, Wafaa M

    2009-10-01

    Liposomes have been used as delivery vehicles for stabilizing drugs, overcoming barriers to cellular and tissue uptake, and for directing their contents toward specific sites in vivo. Chitosan is a biological macromolecule derived from crustacean shells and has several emerging applications in drug development, obesity control, and tissue engineering. In the present work, the interaction between chitosan and dipalmitoyl phosphatidylcholine (DPPC) liposomes was studied by transmission electron microscopy (TEM), zeta potential, solubilization using the nonionic detergent octylglucoside (OG), as well as Fourier transform infrared (FTIR) spectroscopy and viscosity measurements. The coating of DPPC liposomes by a chitosan layer was confirmed by electron microscope images and the zeta potential of liposomes. Coating of liposome by chitosan resulted in an increase in liposomal size by addition of a layer of 92 +/- 27.1 nm. The liposomal zeta potential became increasingly positive as chitosan concentration increased from 0.1 to 0.3% w/v, then it held at a relatively constant value. The amount of detergent needed to completely solubilize the liposomal membrane was increased after coating of liposomes with chitosan, indicating an increased membrane resistance to the detergent and hence a change in the natural membrane permeation properties. In the analysis of FTIR spectra of DPPC, the symmetric and antisymmetric CH(2) (at 2,800-3,000 cm(-1)) bands and the C=O (at 1,740 cm(-1)) stretching band were investigated in the absence and presence of the chitosan. It was concluded that appropriate combining of the liposomal and chitosan characteristics might be utilized for the improvement of the therapeutic efficacy of liposomes as a drug delivery system. PMID:19649627

  4. Genetic Analysis in Maize Foundation Parents with Mapping Population and Testcross Population: Ye478 Carried More Favorable Alleles and Using QTL Information Could Improve Foundation Parents

    Science.gov (United States)

    Liu, Yinghong; Hou, Xianbin; Xiao, Qianlin; Yi, Qiang; Bian, Shaowei; Hu, Yufeng; Liu, Hanmei; Zhang, Junjie; Hao, Xiaoqin; Cheng, Weidong; Li, Yu; Huang, Yubi

    2016-01-01

    The development of maize foundation parents is an important part of genetics and breeding research, and applying new genetic information to produce foundation parents has been challenging. In this study, we focused on quantitative trait loci (QTLs) and general combining ability (GCA) of Ye478, a widely used foundation parent in China. We developed three sets of populations for QTL mapping and to analyze the GCA for some agronomic traits. The assessment of 15 traits resulted in the detection of 251 QTLs in six tested environments, with 119 QTLs identified through a joint analysis across all environments. Further, analyses revealed that most favorable alleles for plant type-related traits were from Ye478, and more than half of the favorable alleles for yield-related traits were from R08, another foundation parent used in southwestern China, suggesting that different types of foundation parents carried different favorable alleles. We observed that the GCA for most traits (e.g., plant height and 100-kernel weight) was maintained in the inbred lines descended from the foundation parents. Additionally, the continuous improvement in the GCA of the descendants of the foundation parents was consistent with the main trend in maize breeding programs. We identified three significant genomic regions that were highly conserved in three Ye478 descendants, including the stable QTL for plant height. The GCA for the traits in the F7 generation revealed that the QTLs for the given traits per se were affected by additive effects in the same way in different populations. PMID:27721817

  5. The effect of managing improved fallows of Mucuna pruriens on maize production and soil carbon and nitrogen dynamics in sub-humid Zimbabwe

    NARCIS (Netherlands)

    Whitbread, A.M.; Jiri, O.; Maasdorp, B.

    2004-01-01

    Mucuna pruriens has emerged as a successful forage or green manure legume for use in the smallholder animal-livestock systems of Zimbabwe. The efficiency of N recovery from mucuna residues in subsequent maize crops can be low and the loss of nitrate nitrogen from the soil profile prior to maize N de

  6. Preparation of chitosan gel

    Directory of Open Access Journals (Sweden)

    Lagerge S.

    2012-06-01

    Full Text Available Aerogel conditioning of the chitosan makes it possible to prepare porous solids of significant specific surface. The increase in the chitosan concentration or the degree of acetylation decreases the specific surface of the synthesized chitosan gel. Whereas drying with supercritical CO2 more effectively makes it possible to preserve the volume of the spheres of gel and to have a more significant specific surface in comparison with evaporative drying.

  7. Preparation, characterization and antibacterial activity of chitosan and phosphorylated chitosan from cuttlebone of Sepia kobiensis (Hoyle, 1885

    Directory of Open Access Journals (Sweden)

    Annaian Shanmugam

    2016-03-01

    Full Text Available Chitosan is a commercially available derivative of chitin that has been extensively studied for its antimicrobial properties. In order to improve the water solubility and its biological activity, the chemical modification or derivatisation is attempted. In the present investigation, the chitosan prepared from the cuttlebone of Sepia kobiensis was being chemically modified by reacting it with orthophosphoric acid so as to obtain phosphorylated chitosan. Then the chitosan and phosphorylated chitosan were structurally characterized through FT-IR spectroscopy. Further the antibacterial activity of chitosan and phosphorylated chitosan was tested against clinically isolated human pathogens (Gram-positive: Streptococcus sp., Streptococcus pneumoniae and Staphylococcus aureus and Gram-negative: Escherichia coli, Vibrio cholerae, V. alginolyticus, Vibrio parahaemolyticus, Pseudomonas aeruginosa, Klebsiella pneumoniae, Salmonella sp. and Proteus vulgaris by well diffusion method and the Minimum Inhibitory Concentration (MIC was also calculated. The results of the present study suggests that the chitosan and phosphorylated chitosan has concentration dependent antibacterial activity with variation against several pathogenic human pathogenic bacterial strains which indicates their possible use as antibacterial agents.

  8. Effect of Spatial Arrangement on Growth and Yield of Cowpea in a Cowpea-maize Intercrop

    Directory of Open Access Journals (Sweden)

    Ocaya, CP.

    2001-01-01

    Full Text Available Cowpea growth and yield performance when intercropped with maize was studied for 3 consecutive seasons under three spatial arrangements, i. e., maize planted at 90 x 30, 100 x 27, and 120 x 22.5 cm, with 2 rows of cowpea between the maize rows. Growth and yield of cowpea was improved significantly by widening maize intra-row distances as compared to the 90 x 30 cm spacing. Hence, intercropped cowpea needs to be sown where maize rows are wide apart, but the maize rows should not be too wide as this would lower the grain yield of maize.

  9. Salt stress in maize: effects, resistance mechanisms, and management. A review

    OpenAIRE

    Farooq, Muhammad; Hussain, Mubshar; Wakeel, Abdul; Kadambot H M Siddique

    2015-01-01

    Maize is grown under a wide spectrum of soil and climatic conditions. Maize is moderately sensitive to salt stress; therefore, soil salinity is a serious threat to its production worldwide. Understanding maize response to salt stress and resistance mechanisms and overviewing management options may help to devise strategies for improved maize performance in saline environments. Here, we reviewed the effects, resistance mechanisms, and management of salt stress in maize. Our main conclusions ar...

  10. "Bio-glues" to Enhance Slipperiness of Mucins: Improved Lubricity and Wear Resistance of Porcine Gastric Mucin (PGM) Layers Assisted by Mucoadhesion with Chitosan

    DEFF Research Database (Denmark)

    Nikogeorgos, Nikolaos; Efler, Petr; Lee, Seunghwan;

    2015-01-01

    A synergetic lubricating effect between porcine gastric mucin (PGM) and chitosan based on their mucoadhesive interaction is reported at a hydrophobic interface comprised of self-mated polydimethylsiloxane (PDMS) surfaces. In acidic solution (pH 3.2) and low concentrations (0.1 mg mL- 1), the inte......A synergetic lubricating effect between porcine gastric mucin (PGM) and chitosan based on their mucoadhesive interaction is reported at a hydrophobic interface comprised of self-mated polydimethylsiloxane (PDMS) surfaces. In acidic solution (pH 3.2) and low concentrations (0.1 mg mL- 1...

  11. Degradation and compatibility behaviors of poly(glycolic acid) grafted chitosan

    International Nuclear Information System (INIS)

    The films of poly(glycolic acid) grafted chitosan were prepared without using a catalyst to improve the degradable property of chitosan. The films were characterized by Fourier transform-infrared spectroscopy and X-ray photoelectron spectroscopy (XPS). The degradation of the poly(glycolic acid) grafted chitosan films were investigated in the lysozyme solution. In vitro degradation tests revealed that the degradation rate of poly(glycolic acid) grafted chitosan films increased dramatically compared with chitosan. The degradation rate of poly(glycolic acid) grafted chitosan films gradually increased with the increasing of the molar ratio of glycolic acid to chitosan. Additionally, the poly(glycolic acid) grafted chitosan films have good biocompatibility, as demonstrated by in vitro cytotoxicity of the extraction fluids. The biocompatible and biodegradable poly(glycolic acid) grafted chitosan would be an effective material with controllable degradation rate to meet the diverse needs in biomedical fields. - Highlights: ► Chitosan-g-poly(glycolic acid) copolymer was prepared without using a catalyst. ► Degradation rate of copolymer increased dramatically compared with that of chitosan. ► Degradation rate was controlled by the molar ratio of glycolic acid to chitosan. ► In vitro cytotoxicity tests revealed that the copolymer has good biocompatibility. ► The copolymer has a great potential to meet diverse needs in biomedical fields

  12. Degradation and compatibility behaviors of poly(glycolic acid) grafted chitosan

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Luzhong; Dou, Sufeng [Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong 226001 (China); Li, Yan [College of Life Science and Pharmaceutical Engineering, Nanjing University of Technology, Nanjing 210009 (China); Yuan, Ying; Ji, Yawei [Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong 226001 (China); Wang, Yaling [College of Chemistry and Chemical Engineering, Nantong University, Nantong 226001 (China); Yang, Yumin, E-mail: yangym@ntu.edu.cn [Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong 226001 (China)

    2013-07-01

    The films of poly(glycolic acid) grafted chitosan were prepared without using a catalyst to improve the degradable property of chitosan. The films were characterized by Fourier transform-infrared spectroscopy and X-ray photoelectron spectroscopy (XPS). The degradation of the poly(glycolic acid) grafted chitosan films were investigated in the lysozyme solution. In vitro degradation tests revealed that the degradation rate of poly(glycolic acid) grafted chitosan films increased dramatically compared with chitosan. The degradation rate of poly(glycolic acid) grafted chitosan films gradually increased with the increasing of the molar ratio of glycolic acid to chitosan. Additionally, the poly(glycolic acid) grafted chitosan films have good biocompatibility, as demonstrated by in vitro cytotoxicity of the extraction fluids. The biocompatible and biodegradable poly(glycolic acid) grafted chitosan would be an effective material with controllable degradation rate to meet the diverse needs in biomedical fields. - Highlights: ► Chitosan-g-poly(glycolic acid) copolymer was prepared without using a catalyst. ► Degradation rate of copolymer increased dramatically compared with that of chitosan. ► Degradation rate was controlled by the molar ratio of glycolic acid to chitosan. ► In vitro cytotoxicity tests revealed that the copolymer has good biocompatibility. ► The copolymer has a great potential to meet diverse needs in biomedical fields.

  13. Mechanisms of chitosan-coated poly(lactic-co-glycolic acid) nanoparticles for improving oral absorption of 7-ethyl-10-hydroxycamptothecin

    Science.gov (United States)

    Guo, Miao; Rong, Wen-Ting; Hou, Jie; Wang, Dong-Fang; Lu, Yu; Wang, Ying; Yu, Shu-Qin; Xu, Qian

    2013-06-01

    Chitosan-modified poly(lactic-co-glycolic acid) nanoparticles (CHI/PLGA NPs) loaded with 7-ethyl-10-hydroxycamptothecin (SN-38), named CHI/PLGA/SN-38 NPs, were successfully prepared using an oil-in-water (O/W) solvent evaporation method. The physicochemical properties of the novel NPs were characterized by DLS, Zeta potential, SEM, DSC, XRD, and FTIR. The encapsulation efficiency and drug loading content were 71.83 (±2.77)% and 6.79 (±0.26)%, respectively. In vitro drug release in the simulated gastric juice was lower than that in the intestinal juice. In situ single-pass intestinal perfusion (SPIP) studies indicated a dramatic improvement of drug absorption as a result of the synergistic effect between CHI and PLGA on P-glycoprotein (Pgp) inhibition. CHI/PLGA NPs showed high cellular uptake and low efflux for drugs in Caco-2 cells. The cytotoxicity studies revealed that CHI/PLGA NPs had a transient effect on the membrane integrity, but did not have an influence on cell viability. Based on the in vitro release studies, SPIP, and intracellular drug accumulation and transport investigations, we speculate rationally that CHI/PLGA NPs were mainly internalized in the form of intact NPs, thus escaping the recognition of enterocyte Pgp and avoiding efflux into the apical part of the enterocytes. After partial release of drugs inside the enterocytes, CHI/PLGA interfered with the microenvironment of Pgp and further weakened the Pgp-mediated efflux. Then, the drug-loaded NPs exited via the exocytose effect from the basal part of the enterocytes and entered the blood circulation. These results showed that CHI/PLGA NPs would be smart oral delivery carriers for antineoplastic agents that are also Pgp substrates.

  14. Transient aggregation of chitosan-modified poly(d,l-lactic-co-glycolic) acid nanoparticles in the blood stream and improved lung targeting efficiency.

    Science.gov (United States)

    Lee, Song Yi; Jung, Eunjae; Park, Ju-Hwan; Park, Jin Woo; Shim, Chang-Koo; Kim, Dae-Duk; Yoon, In-Soo; Cho, Hyun-Jong

    2016-10-15

    Chitosan (CS)-modified poly(d,l-lactic-co-glycolic) acid (PLGA) nanoparticles (NPs) were prepared and their lung targetability after intravenous administration was elucidated. PLGA NPs (mean diameter: 225nm; polydispersity index: 0.11; zeta potential: -15mV), 0.2% (w/v) CS-coated PLGA NPs (CS02-PLGA NPs, mean diameter: 264nm; polydispersity index: 0.17; zeta potential: -7mV), and 0.5% (w/v) CS-coated PLGA NPs (CS05-PLGA NPs, mean diameter: 338nm; polydispersity index: 0.23; zeta potential: 12mV) were fabricated by a modified solvent evaporation method. PLGA NPs maintained their initial particle size in different media, such as human serum albumin (HSA) solution, rat plasma, and distilled water (DW), while CS05-PLGA NPs exhibited the formation of aggregates in early incubation time and disassembly of those into the NPs in late incubation time (at 24h). According to the sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis, the binding affinity of CS05-PLGA NPs with HSA and rat plasma was higher than that of PLGA NPs. By a near-infrared fluorescence (NIRF) imaging test in the mouse, the selective accumulation of CS05-PLGA NPs, rather than PLGA NPs, in lung tissue was demonstrated. These findings suggest that CS05-PLGA NPs can form transient aggregates in the blood stream after intravenous administration and markedly improve lung targeting efficiency, compared with PLGA NPs. PMID:27421112

  15. Ensifer meliloti overexpressing Escherichia coli phytase gene ( appA) improves phosphorus (P) acquisition in maize plants

    Science.gov (United States)

    Sharma, Vikas; Kumar, Ajit; Archana, G.; Kumar, G. Naresh

    2016-10-01

    The Escherichia coli phytase gene appA encoding enzyme AppA was cloned in a broad host range plasmid pBBR1MCS2 ( lac promoter), termed pVA1, and transformed into the Ensifer meliloti 1020. Transformation of pVA1 in Ensifer meliloti { E. m (pVA1)} increased its phosphatase and phytase activity by ˜9- and ˜50-fold, respectively, compared to the transformants containing empty plasmid as control { E. m (pBBR1MCS2)}. The western blot experiments using rabbit anti-AppA antibody showed that AppA is translocated into the periplasm of the host after its expression. Ensifer meliloti harboring AppA protein { E. m (pVA1)} and { E. m (pBBR1MCS2)} could acidify the unbuffered phytate minimal media (pH 8.0) containing Ca-phytate or Na-phytate as sole organic P (Po) source to below pH 5.0 and released P. However, both { E. m (pVA1)} and { E. m (pBBR1MCS2)} neither dropped pH of the medium nor released P when the medium was buffered at pH 8.0 using Tris-Cl, indicating that acidification of medium was important for the enzymatic hydrolysis of phytate. Further experiments proved that maize plants inoculated with { E. m. (pVA1)} showed increase in growth under sterile semi solid agar (SSA) medium containing Na-phytate as sole P source. The present study could be helpful in generating better transgenic bioinoculants harboring phosphate mineralization properties that ultimately promote plant growth.

  16. Maize silage supplementation to lower quality grass silage improves the intake, apparent digestibility and N retention in wether sheep

    Directory of Open Access Journals (Sweden)

    Ivana Matić

    2009-12-01

    Full Text Available The objective of this experiment was to study the effects of interactions between lower quality grass silage (GS dominated by orchardgrass (Dactylis glomerata L. and maize silage (MS (Zea mays L. on ad libitum intake, digestibility and N retention in wether sheep. The study consisted of four feeding treatments involving GS and MS alone, and GS and MS mixtures in ratios of 67:33 or 33:67 (DM basis fed twice daily. The GS was harvested at the beginning of flowering of orchardgrass (about 35 % of plants were in flower while the MS used was of lower DM and starch concentration (264 g kg-1 fresh weight and 211 g kg-1 DM respectively. Mean DM content of GS was 408 g kg-1 fresh weight. MS was lower in crude protein (CP (62 g kg-1 DM than the GS (98 g kg-1 DM (P<0.001. GS contained larger quantities of neutral detergent fibre (NDF and acid detergent fiber (ADF (P<0.001 than MS. Inclusion of MS in the diet (33 % vs. 67 % had positive linear effects on fresh matter (FM voluntary intake (P<0.05, digestibility of DM, organic matter (OM, digestible OM in the DM (D-value (P<0.05, starch digestibility (P<0.05, N intake (P<0.01, N output in faeces (P<0.05 and absorbed N (P<0.05. A positive associative effect of GS and MS was observed for all intake parameters measured (FM, DM, OM, NDF (quadratic, P<0.05 to P<0.01, digestibility of DM, ADF (quadratic, P<0.05, CP (quadratic, P<0.01, N intake and absorbed N (quadratic, P<0.01. It was concluded that positive interactions of GS and MS were recorded for a limited number of parameters because of the lower quality MS than required for the full benefit of two forages fed together.

  17. Cell-wall properties contributing to improved deconstruction by alkaline pre-treatment and enzymatic hydrolysis in diverse maize (Zea mays L.) lines

    OpenAIRE

    Li, Muyang; Heckwolf, Marlies; Crowe, Jacob D.; Williams, Daniel L.; Magee, Timothy D.; Shawn M Kaeppler; Leon, Natalia de; Hodge, David B

    2015-01-01

    A maize (Zea mays L. subsp. mays) diversity panel consisting of 26 maize lines exhibiting a wide range of cell-wall properties and responses to hydrolysis by cellulolytic enzymes was employed to investigate the relationship between cell-wall properties, cell-wall responses to mild NaOH pre-treatment, and enzymatic hydrolysis yields. Enzymatic hydrolysis of the cellulose in the untreated maize was found to be positively correlated with the water retention value, which is a measure of cell-wall...

  18. Modified chitosans for biomedical applications

    OpenAIRE

    Yalınca, Zülal

    2013-01-01

    ABSTRACT: The subject of this thesis is the exploration of the suitability of chitosan and some of its derivatives for some chosen biomedical applications. Chitosan-graft-poly (N-vinyl imidazole), Chitosan-tripolyphosphate and ascorbyl chitosan were synthesized and characterized for specific biomedical applications in line with their chemical functionalities. Chitosan-graft-poly (N-vinyl imidazole), Chi-graft-PNVI, was synthesized by two methods; via an N-protection route and without N-pr...

  19. Modification of chitosan by swelling and crosslinking using epichlorohydrin as heavy metal Cr (VI) adsorbent in batik industry wastes

    Science.gov (United States)

    Hastuti, B.; Masykur, A.; Hadi, S.

    2016-02-01

    Study on chitosan modification by swelling and crosslinking and its application as a selective adsorbent for heavy metals Cr (VI) in batik industry wastes was done. Swelling is intended to improve chitosan porosity, whereas crosslinking is to increase the resistance of chitosan against acid. Natural samples are generally acidic, thus limiting chitosan application as an adsorbent. Modification of chitosan by combining swelling and crosslinking is expected to increase its adsorption capacity in binding heavy metal ions in water. The modified chitosan was later contacted with Cr (VI) to test its adsorption capacity with a variation of pH and contact time. Finally, application of modified chitosan was done in batik industry waste containing Cr (IV). Based on the results, chitosan-ECH 25% (v/v) was the optimum concentration of crosslinker to adsorb Cr (VI) ions. Modified chitosan has a solubility resistance to acids, even though a strong acid. Modification of chitosan also improved its adsorption capacity to Cr (VI) from 74% (pure chitosan) to 89% with contact time 30 min at pH 3. On the application to the batik wastes, the modified chitosan were able to adsorb Cr (IV) up to the level of 5 ppm. Thus, the modified chitosan has a potential to be applied to as an adsorbent of Cr (VI) in batik industry wastes.

  20. PREPARATION AND PROPERTIES OF CHITOSAN/LIGNIN COMPOSITE FILMS

    Institute of Scientific and Technical Information of China (English)

    Long Chen; Chang-yu Tang; Nan-ying Ning; Chao-yu Wang; Qiang Fu; Qin Zhang

    2009-01-01

    Biodegradable composite films based on chitosan and lignin with various composition were prepared via the solution-casting technique.FT-IR results indicate the existence of hydrogen bonding between chitosan and lignin,and SEM images show that lignin could be well dispersed in chitosan when the content of lignin is below 20 wt% due to the strong interfacial interaction.As a result of strong interaction and good dispersion,the tensile strength,storage modulus,thermal degradation temperature and glass transition temperature of chitosan have been largely improved by adding lignin.Our work provides a simple and cheap way to prepare fully biodegradable chitosan/lignin composites,which could be used as packaging films or wound dressings.

  1. Preparation and mechanical properties of chitosan/carbon nanotubes composites.

    Science.gov (United States)

    Wang, Shao-Feng; Shen, Lu; Zhang, Wei-De; Tong, Yue-Jin

    2005-01-01

    Biopolymer chitosan/multiwalled carbon nanotubes (MWNTs) nanocomposites have been successfully prepared by a simple solution-evaporation method. The morphology and mechanical properties of the chitosan/MWNTs nanocomposites have been characterized with field emission scanning electron microscopy (SEM), bright field transmission electron microscopy (TEM), optical microscopy (OM), wide-angle X-ray diffraction (XRD), and tensile as well as nanoindentation tests. The MWNTs were observed to be homogeneously dispersed throughout the chitosan matrix. When compared with neat chitosan, the mechanical properties, including the tensile modulus and strength, of the nanocomposites are greatly improved by about 93% and 99%, respectively, with incorporation of only 0.8 wt % of MWNTs into the chitosan matrix. PMID:16283728

  2. Preparation and properties of polyvinyl acetal sponge modified by chitosan

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The polyvinyl acetal sponge modified by chitosan was prepared by adding chitosan/polyvinyl alcohol (PVA) solution during the acetalation reaction of PVA and formaldehyde.The effect of vesicant and chitosan to the pore morphology,water absorption ratio,water absorption rate,expansion time and mechanical properties were studied.The polyvinyl acetal sponge modified by chitosan was used as a hemostatic packing material for the injured rabbit nasal tissue.The hemostatic effect and the healing effect of the modified sponge on the nasal mucosa after nasal surgery were studied.The results indicated that the polyvinyl acetal sponge modified by chitosan has an interconnected pore structure and the wall between large pores also has small pores.The chitosan adhered on the inner surface of the pores.The increased content of vesicant led to an increase in pore diameter,in the water absorption ratio and in expansion time.However,there was only a small change in the water absorption rate and a decrease in tensile strength and compression strength were noted.With an increase in chitosan content,the pore diameter and interconnection of the sponge was reduced.Water absorption ratio,expansion time and water absorption rate decreased,but tensile strength and compression strength improved.Observation of the rabbit nasal tissue after surgical operation suggested that polyvinyl acetal sponge modified by chitosan has an anti-inflammatory,hemostatic and antiadherent characteristic and could promote the healing and functional recovery of rabbit nasal mucosa.

  3. Air plasma treated chitosan fibers-stacked scaffolds

    International Nuclear Information System (INIS)

    Chitosan is a nontoxic, biodegradable and biocompatible polymer. Rapid prototyped chitosan scaffolds were manufactured by liquid-frozen deposition of chitosan fibers in this study. To investigate if the air plasma (AP) treatment could be used to improve the surface properties of these scaffolds for cell attachment, chitosan films were first prepared and treated with AP under different conditions. Under the optimized condition, the water contact angle of chitosan films was significantly reduced from 90 ± 1° to 19 ± 1° after AP treatment. On the other hand, the surface charge and nanometric roughness of chitosan films increased after AP treatment. X-ray photoelectron spectroscopy measurement on AP-treated three-dimensional chitosan scaffolds showed that nitrogen and oxygen increased at each location inside the scaffolds as compared to the untreated ones, which indicated that AP could permeate through the fibrous stacks of the scaffolds and effectively modify the interior (visible) surface of the scaffolds. Moreover, AP treatment enabled the migration of MC3T3-E1 cells into the scaffolds, facilitated their proliferation and promoted the bone mineral deposition. These results suggested that fibers-stacked chitosan scaffolds may be produced by liquid-frozen deposition and treated with AP for bone tissue engineering applications. (paper)

  4. Application of organic matter and biofertilizer to improve growth and yield of maize on soil damaged by volcanic ash of Mount Kelud in East Java

    OpenAIRE

    S. Hardianita; R.M. Bosas; Y. Nuraini

    2015-01-01

    Volcanic ash from the eruption of Mount Kelud in 2014 damaged some agricultural areas grown with maize in Malang of East Java. The purpose of this study was to elucidate the effect of organic fertilizers and biological fertilizers on growth and yield of maize on soils damaged by volcanic ash from the eruption of Mount Kelud. A pot experiment was conducted in the glasshouse of Balitkabi, Kendalpayak, Malang from July 2014 to February 2015. The treatments tested in this study were combinations ...

  5. Woody legume fallow productivity, biological N2-fixation and residual benefits to two successive maize crops in Zimbabwe

    NARCIS (Netherlands)

    Chikowo, R.; Mapfumo, P.; Nyamugafata, P.; Giller, K.E.

    2004-01-01

    Three woody legumes were planted as two-year 'improved fallows' to evaluate their residual nitrogen (N) effects on two subsequent maize crops under minimum and conventional tillage management. Maize monoculture and cowpea-maize-maize sequence treatments were included as controls. N-2-fixation was es

  6. Preparation and properties of chitosan nanocomposite films reinforced by poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) treated carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Wu Tongfei; Pan Yongzheng; Bao Hongqian [School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 (Singapore); Li Lin, E-mail: mlli@ntu.edu.sg [School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 (Singapore)

    2011-10-03

    Highlights: {yields} Chitosan-based nanocomposites prepared from PEDOT-PSS treated MWCNTs. {yields} PEDOT-PSS served as a bridge to improve the dispersion of MWCNTs and interfacial compatibility between MWCNTs and chitosan. {yields} The mechanical properties of chitosan were significantly improved by PEDOT-PSS treated MWCNTs at a small loading. - Abstract: Carbon nanotube-based nanocomposites of chitosan were successfully prepared by a simple solution-evaporation method. Multiwalled carbon nanotubes (MWCNTs) were treated by poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate)(PEDOT-PSS) in water before mixed with a chitosan solution to improve the dispersion of MWCNTs and interfacial compatibility between MWCNTs and chitosan. The morphological and mechanical properties of the prepared PEDOT-PSS/MWCNT/chitosan nanocomposites have been characterized with field emission scanning electron microscopy (FESEM) and tensile tests. MWCNTs were observed to be homogeneously dispersed throughout the chitosan matrix. As compared with the neat chitosan, the tensile strength and modulus of the nanocomposite were greatly improved by about 61% and 34%, respectively, with incorporation of only 0.5 wt.% of MWCNTs into the chitosan matrix. The comparison of mechanical properties for PEDOT-PSS/MWCNT/chitosan and pristine MWCNT/chitosan nanocomposites has been made. The hardness of the nanocomposites was also evaluated by nanoindentation.

  7. Preparation and properties of chitosan nanocomposite films reinforced by poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) treated carbon nanotubes

    International Nuclear Information System (INIS)

    Highlights: → Chitosan-based nanocomposites prepared from PEDOT-PSS treated MWCNTs. → PEDOT-PSS served as a bridge to improve the dispersion of MWCNTs and interfacial compatibility between MWCNTs and chitosan. → The mechanical properties of chitosan were significantly improved by PEDOT-PSS treated MWCNTs at a small loading. - Abstract: Carbon nanotube-based nanocomposites of chitosan were successfully prepared by a simple solution-evaporation method. Multiwalled carbon nanotubes (MWCNTs) were treated by poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate)(PEDOT-PSS) in water before mixed with a chitosan solution to improve the dispersion of MWCNTs and interfacial compatibility between MWCNTs and chitosan. The morphological and mechanical properties of the prepared PEDOT-PSS/MWCNT/chitosan nanocomposites have been characterized with field emission scanning electron microscopy (FESEM) and tensile tests. MWCNTs were observed to be homogeneously dispersed throughout the chitosan matrix. As compared with the neat chitosan, the tensile strength and modulus of the nanocomposite were greatly improved by about 61% and 34%, respectively, with incorporation of only 0.5 wt.% of MWCNTs into the chitosan matrix. The comparison of mechanical properties for PEDOT-PSS/MWCNT/chitosan and pristine MWCNT/chitosan nanocomposites has been made. The hardness of the nanocomposites was also evaluated by nanoindentation.

  8. Chitosan and chitosan chlorhydrate based various approaches for enhancement of dissolution rate of carvedilol

    Directory of Open Access Journals (Sweden)

    Shete Amol S

    2012-12-01

    Full Text Available Abstract Background and the purpose of the study Carvedilol nonselective β-adrenoreceptor blocker, chemically (±-1-(Carbazol-4-yloxy-3-[[2-(o-methoxypHenoxy ethyl] amino]-2-propanol, slightly soluble in ethyl ether; and practically insoluble in water, gastric fluid (simulated, TS, pH 1.1, and intestinal fluid (simulated, TS without pancreatin, pH 7.5 Compounds with aqueous solubility less than 1% W/V often represents dissolution rate limited absorption. There is need to enhance the dissolution rate of carvedilol. The objective of our present investigation was to compare chitosan and chitosan chlorhydrate based various approaches for enhancement of dissolution rate of carvedilol. Methods The different formulations were prepared by different methods like solvent change approach to prepare hydrosols, solvent evaporation technique to form solid dispersions and cogrind mixtures. The prepared formulations were characterized in terms of saturation solubility, drug content, infrared spectroscopy (FTIR, differential scanning calorimetry (DSC, powder X-ray diffraction (PXRD, electron microscopy, in vitro dissolution studies and stability studies. Results The practical yield in case of hydrosols was ranged from 59.76 to 92.32%. The drug content was found to uniform among the different batches of hydrosols, cogrind mixture and solid dispersions ranged from 98.24 to 99.89%. There was significant improvement in dissolution rate of carvedilol with chitosan chlorhdyrate as compare to chitosan and explanation to this behavior was found in the differences in the wetting, solubilities and swelling capacity of the chitosan and chitosan salts, chitosan chlorhydrate rapidly wet and dissolve upon its incorporation into the dissolution medium, whereas the chitosan base, less water soluble, would take more time to dissolve. Conclusion This technique is scalable and valuable in manufacturing process in future for enhancement of dissolution of poorly water soluble

  9. Characterization and potential applications of gamma irradiated chitosan and its blends with poly(vinyl alcohol).

    Science.gov (United States)

    Bano, Ijaz; Ghauri, Muhammad Afzal; Yasin, Tariq; Huang, Qingrong; Palaparthi, Annie D'Souza

    2014-04-01

    Naturally available chitosan (CHI), of high molecular weight, results in reduced efficiency of these polymers for antibacterial activity. In this regard, irradiation is a widely used method for achieving reduction in molecular weight of polymers, which may improve some of its characteristics. Chitosan was extracted from crab shells and degraded by gamma radiations. Effect of radiation dose on chitosan was analyzed by Fourier transform infrared (FTIR) spectroscopy. Furthermore, the irradiated chitosan was blended with poly(vinyl alcohol) (PVA) and crosslinked with tetraethylorthosilicate (TEOS) into membranes. The membranes were found to be smooth, transparent and macroporous in structure, exhibiting high tensile strength (TS: 27-47 MPa) and elongation at break (EB: 292.6-407.3%). The effect of molecular weight of chitosan and chitosan blends on antibacterial activity was determined. Irradiated low molecular weight chitosan and membranes showed strong antibacterial activity against Escherichia coli and Bacillus subtilis.

  10. Effect of organic fertilizers on maize production in Eastern Georgia

    Science.gov (United States)

    Jolokhava, Tamar; Kenchiashvili, Naira; Tarkhnishvili, Maia; Ghambashidze, Giorgi

    2016-04-01

    Maize remains to be the most important cereal crop in Georgia. Total area of arable land under cereal crops production equals to 184 thousands hectares (FAO statistical yearbook, 2014), from which maize takes the biggest share. Leading position of maize among other cereal crops is caused by its dual purpose as food and feed product. In Spite of a relatively high production of maize to other cereals there is still a high demand on it, especially as feed for animal husbandry. The same tendency is seen in organic production, where producers of livestock and poultry products require organically grown maize, the average yield of which is much less than those produced conventionally. Therefore, it is important to increase productivity of maize in organic farms. Current study aimed to improve maize yield using locally produced organic fertilizers and to compare them to the effect of mineral fertilizers. The study was carried out in Eastern Georgia under dry subtropical climate conditions on local hybrid of maize. This is the first attempt to use hybrid maize (developed with organic plant breeding method) in organic field trials in Georgia. The results shown, that grain yield from two different types of organic fertilizers reached 70% of the yields achieved with industrial mineral fertilizers. As on farm level differences between organic and conventional maize production are much severe, the results from the field trials seems to be promising for future improvement of organic cereal crop production.

  11. The effect of calcium and chitosan metabolism to the excretion of radiostrontium in mice

    International Nuclear Information System (INIS)

    Chitosan, a natural nontoxic chelator, was reported to reduce whole body retention of radiostrontium in mice. As calcium has a similar chemical properties to strontium both of which be easily bound with hydroxyapatite structure, calcium can be either a competitor or enhancer to chitosan on the removal of radiostrontium. We compared the effect of chitosan and calcium on the excretion of ingested radiostrontium (85Sr). Chitosan or calcium(CaCl2) and usual food was mixed as 1:99 by weight. The mixed food to chitosan(group 1) or calcium(group 2) were given orally for 30 days before 85Sr administration. In other groups, mixed calcium and chitosan solution (group 3), 1% calcium (group 4), or 1% chitosan solution (group 5) was given for 7 days immediately after oral administration of 85SrCl2 (0.25μCi). In control group, no chitosan or calcium were given. Either chitosan or calcium was effective on the removal of 85Sr from mouse body (Table 1). Addition of calcium on chitosan did not improve or deteriorate the effect of chitosan on the removal of 85Sr from mouse body. In conclusion, calcium was similarly effective on the removal of 85Sr from mouse body. (author)

  12. Reshaping of the maize transcriptome by domestication.

    Science.gov (United States)

    Swanson-Wagner, Ruth; Briskine, Roman; Schaefer, Robert; Hufford, Matthew B; Ross-Ibarra, Jeffrey; Myers, Chad L; Tiffin, Peter; Springer, Nathan M

    2012-07-17

    Through domestication, humans have substantially altered the morphology of Zea mays ssp. parviglumis (teosinte) into the currently recognizable maize. This system serves as a model for studying adaptation, genome evolution, and the genetics and evolution of complex traits. To examine how domestication has reshaped the transcriptome of maize seedlings, we used expression profiling of 18,242 genes for 38 diverse maize genotypes and 24 teosinte genotypes. We detected evidence for more than 600 genes having significantly different expression levels in maize compared with teosinte. Moreover, more than 1,100 genes showed significantly altered coexpression profiles, reflective of substantial rewiring of the transcriptome since domestication. The genes with altered expression show a significant enrichment for genes previously identified through population genetic analyses as likely targets of selection during maize domestication and improvement; 46 genes previously identified as putative targets of selection also exhibit altered expression levels and coexpression relationships. We also identified 45 genes with altered, primarily higher, expression in inbred relative to outcrossed teosinte. These genes are enriched for functions related to biotic stress and may reflect responses to the effects of inbreeding. This study not only documents alterations in the maize transcriptome following domestication, identifying several genes that may have contributed to the evolution of maize, but highlights the complementary information that can be gained by combining gene expression with population genetic analyses.

  13. Improvement of grape and wine phenolic content by foliar application to grapevine of three different elicitors: Methyl jasmonate, chitosan, and yeast extract.

    Science.gov (United States)

    Portu, Javier; López, Rosa; Baroja, Elisa; Santamaría, Pilar; Garde-Cerdán, Teresa

    2016-06-15

    Phenolic compounds play a key role in grape and wine organoleptic properties, being therefore a key parameter in wine quality. Elicitor application constitutes an interesting field of research since it is indirectly involved in the accumulation of phenolic compounds. The aim of this study was to compare the effect of the application of three different elicitors on both grape and wine phenolic content. Methyl jasmonate, chitosan, and a commercial yeast extract were applied to the canopy at veraison and one week later. Results showed that foliar treatments carried out with methyl jasmonate and yeast extract achieved the best results, increasing grape and wine anthocyanin content when compared to the control. Moreover, the application of the yeast elicitor also enhanced grape stilbene content. In contrast, the chitosan treatment did not have a substantial impact on the phenolic compounds. The results of this study indicate that methyl jasmonate and yeast extract applications could be a simple practice to increase grape and wine phenolic content.

  14. Chitosan Removes Toxic Heavy Metal Ions from Cigarette Mainstream Smoke

    Institute of Scientific and Technical Information of China (English)

    ZHOU Wen; XU Ying; WANG Dongfeng; ZHOU Shilu

    2013-01-01

    This study investigated the removal of heavy metal ions from cigarette mainstream smoke using chitosan.Chitosan of various deacetylation degrees and molecular weights were manually added to cigarette filters in different dosages.The mainstream smoke particulate matter was collected by a Cambridge filter pad,digested by a microwave digestor,and then analyzed for contents of heavy metal ions,including As(Ⅲ/Ⅴ),Pb(Ⅱ),Cd(Ⅱ),Cr(Ⅲ/Ⅵ) and Ni(Ⅱ),by graphite furnace atomic absorption spectrometry (GFAAS).The results showed that chitosan had a removal effect on Pb(Ⅱ),Cd(Ⅱ),Cr(Ⅲ/Ⅵ) and Ni(Ⅱ).Of these,the percent removal of Ni(Ⅱ) was elevated with an increasing dosage of chitosan.Chitosan of a high deace tylation degree exhibited good binding performance toward Cd(Ⅱ),Cr(Ⅲ/Ⅵ) and Ni(Ⅱ),though with poor efficiency for Pb(Ⅱ).Except As(Ⅲ/Ⅴ),all the tested metal ions showed similar tendencies in the growing contents with an increasing chitosan molecular weight.Nonetheless,the percent removal of Cr(Ⅲ/Ⅵ) peaked with a chitosan molecular weight of 200 kDa,followed by a dramatic decrease with an increasing chitosan molecular weight.Generally,chitosan had different removal effects on four out of five tested metal ions,and the percent removal of Cd(Ⅱ),Pb(Ⅱ),Cr(Ⅲ/Ⅵ) and Ni(Ⅱ) was approximately 55%,45%,50%,and 16%,respectively.In a word,chitosan used in cigarette filter can remove toxic heavy metal ions in the mainstream smoke,improve cigarette safety,and reduce the harm to smokers.

  15. TRACTION RESISTANCE IN CHITOSAN TREATED COTTON

    Directory of Open Access Journals (Sweden)

    LOX Wouter

    2015-05-01

    Full Text Available Nowadays natural products interest has increased. However, when some products are included on textile fibers, they have no affinity and need some binders or other kind of auxiliaries to improve the yeld of the process, and some of them are not so natural as the product which are binding and consequently the “bio” definition is missed as some of them can be considered as highly pollutant. Chitosan is a common used bonding agent for cotton. It improves the antimicrobial and antifungal activity, improves wound healing and is a non-toxic bonding agent. The biopolymer used in this work is chitosan, which is a deacetylated derivative of chitin. These properties depend on the amount of deacetylation (DD and the Molecular weight (MW. Along with these improving properties, as it requires some acid pH to ve solved the treatment with chitosan can have some decreasing mechanical properties. The aim of that paper is to evaluate the change in breaking force of the treated samples and a change in elongation of those samples. It compared different amounts of concentration of chitosan with non treated cotton. The traction resistance test were performed on a dynamometer. The test was conducted according to the UNE EN ISO 13934-1 standard.

  16. Macrophage interactions with polylactic acid and chitosan scaffolds lead to improved recruitment of human mesenchymal stem/stromal cells: a comprehensive study with different immune cells.

    Science.gov (United States)

    Caires, Hugo R; Esteves, Tiago; Quelhas, Pedro; Barbosa, Mário A; Navarro, Melba; Almeida, Catarina R

    2016-09-01

    Despite the importance of immune cell-biomaterial interactions for the regenerative outcome, few studies have investigated how distinct three-dimensional biomaterials modulate the immune cell-mediated mesenchymal stem/stromal cells (MSC) recruitment and function. Thus, this work compares the response of varied primary human immune cell populations triggered by different model scaffolds and describes its functional consequence on recruitment and motility of bone marrow MSC. It was found that polylactic acid (PLA) and chitosan scaffolds lead to an increase in the metabolic activity of macrophages but not of peripheral blood mononuclear cells (PBMC), natural killer (NK) cells or monocytes. PBMC and NK cells increase their cell number in PLA scaffolds and express a secretion profile that does not promote MSC recruitment. Importantly, chitosan increases IL-8, MIP-1, MCP-1 and RANTES secretion by macrophages while PLA stimulates IL-6, IL-8 and MCP-1 production, all chemokines that can lead to MSC recruitment. This secretion profile of macrophages in contact with biomaterials correlates with the highest MSC invasion. Furthermore, macrophages enhance stem cell motility within chitosan scaffolds by 44% but not in PLA scaffolds. Thus, macrophages are the cells that in contact with engineered biomaterials become activated to secrete bioactive molecules that stimulate MSC recruitment. PMID:27628173

  17. Macrophage interactions with polylactic acid and chitosan scaffolds lead to improved recruitment of human mesenchymal stem/stromal cells: a comprehensive study with different immune cells.

    Science.gov (United States)

    Caires, Hugo R; Esteves, Tiago; Quelhas, Pedro; Barbosa, Mário A; Navarro, Melba; Almeida, Catarina R

    2016-09-01

    Despite the importance of immune cell-biomaterial interactions for the regenerative outcome, few studies have investigated how distinct three-dimensional biomaterials modulate the immune cell-mediated mesenchymal stem/stromal cells (MSC) recruitment and function. Thus, this work compares the response of varied primary human immune cell populations triggered by different model scaffolds and describes its functional consequence on recruitment and motility of bone marrow MSC. It was found that polylactic acid (PLA) and chitosan scaffolds lead to an increase in the metabolic activity of macrophages but not of peripheral blood mononuclear cells (PBMC), natural killer (NK) cells or monocytes. PBMC and NK cells increase their cell number in PLA scaffolds and express a secretion profile that does not promote MSC recruitment. Importantly, chitosan increases IL-8, MIP-1, MCP-1 and RANTES secretion by macrophages while PLA stimulates IL-6, IL-8 and MCP-1 production, all chemokines that can lead to MSC recruitment. This secretion profile of macrophages in contact with biomaterials correlates with the highest MSC invasion. Furthermore, macrophages enhance stem cell motility within chitosan scaffolds by 44% but not in PLA scaffolds. Thus, macrophages are the cells that in contact with engineered biomaterials become activated to secrete bioactive molecules that stimulate MSC recruitment.

  18. Chitosan in Plant Protection

    OpenAIRE

    Abdelbasset El Hadrami; Adam, Lorne R.; Ismail El Hadrami; Fouad Daayf

    2010-01-01

    Chitin and chitosan are naturally-occurring compounds that have potential in agriculture with regard to controlling plant diseases. These molecules were shown to display toxicity and inhibit fungal growth and development. They were reported to be active against viruses, bacteria and other pests. Fragments from chitin and chitosan are known to have eliciting activities leading to a variety of defense responses in host plants in response to microbial infections, including the accumulation of ph...

  19. Chitosan against cutaneous pathogens

    OpenAIRE

    Champer, Jackson; Patel, Julie; Fernando, Nathalie; Salehi, Elaheh; Wong, Victoria; Kim, Jenny

    2013-01-01

    Propionibacterium acnes and Staphylococcus aureus are cutaneous pathogens that have become increasingly resistant to antibiotics. We sought to determine if chitosan, a polymer of deacetylated chitin, could be used as a potential treatment against these bacteria. We found that higher molecular weight chitosan had superior antimicrobial properties compared to lower molecular weights, and that this activity occurred in a pH dependent manner. Electron and fluorescence microscopy revealed that chi...

  20. Nitrate-N dynamics following improved fallows and maize root development in a Zimbabwean sandy clay loam

    NARCIS (Netherlands)

    Chikowo, R.; Mapfumo, P.; Nyamugafata, P.; Nyamadzawo, G.; Giller, K.E.

    2003-01-01

    Improved or planted fallows using fast-growing leguminous trees are capable of accumulating large amounts of N through biological N 2-fixation and subsoil N capture. During the fallow phase, the cycling of nutrients is largely efficient. However, there are few estimates of the fate of added N during

  1. Genetic Diversity and Molecular Evolution of Chinese Waxy Maize Germplasm

    Science.gov (United States)

    Zheng, Hongjian; Wang, Hui; Yang, Hua; Wu, Jinhong; Shi, Biao; Cai, Run; Xu, Yunbi; Wu, Aizhong; Luo, Lijun

    2013-01-01

    Waxy maize (Zea mays L. var. certaina Kulesh), with many excellent characters in terms of starch composition and economic value, has grown in China for a long history and its production has increased dramatically in recent decades. However, the evolution and origin of waxy maize still remains unclear. We studied the genetic diversity of Chinese waxy maize including typical landraces and inbred lines by SSR analysis and the results showed a wide genetic diversity in the Chinese waxy maize germplasm. We analyzed the origin and evolution of waxy maize by sequencing 108 samples, and downloading 52 sequences from GenBank for the waxy locus in a number of accessions from genus Zea. A sharp reduction of nucleotide diversity and significant neutrality tests (Tajima’s D and Fu and Li’s F*) were observed at the waxy locus in Chinese waxy maize but not in nonglutinous maize. Phylogenetic analysis indicated that Chinese waxy maize originated from the cultivated flint maize and most of the modern waxy maize inbred lines showed a distinct independent origin and evolution process compared with the germplasm from Southwest China. The results indicated that an agronomic trait can be quickly improved to meet production demand by selection. PMID:23818949

  2. Antimicrobial actions of degraded and native chitosan against spoilage organisms in laboratory media and foods.

    Science.gov (United States)

    Rhoades, J; Roller, S

    2000-01-01

    The objective of this study was to determine whether chitosan (poly-beta-1,4-glucosamine) and hydrolysates of chitosan can be used as novel preservatives in foods. Chitosan was hydrolyzed by using oxidative-reductive degradation, crude papaya latex, and lysozyme. Mild hydrolysis of chitosan resulted in improved microbial inactivation in saline and greater inhibition of growth of several spoilage yeasts in laboratory media, but highly degraded products of chitosan exhibited no antimicrobial activity. In pasteurized apple-elderflower juice stored at 7 degrees C, addition of 0.3 g of chitosan per liter eliminated yeasts entirely for the duration of the experiment (13 days), while the total counts and the lactic acid bacterial counts increased at a slower rate than they increased in the control. Addition of 0.3 or 1.0 g of chitosan per kg had no effect on the microbial flora of hummus, a chickpea dip; in the presence of 5.0 g of chitosan per kg, bacterial growth but not yeast growth was substantially reduced compared with growth in control dip stored at 7 degrees C for 6 days. Improved antimicrobial potency of chitosan hydrolysates like that observed in the saline and laboratory medium experiments was not observed in juice and dip experiments. We concluded that native chitosan has potential for use as a preservative in certain types of food but that the increase in antimicrobial activity that occurs following partial hydrolysis is too small to justify the extra processing involved. PMID:10618206

  3. Mixed Compound of DCPTA and CCC Increases Maize Yield by Improving Plant Morphology and Up-Regulating Photosynthetic Capacity and Antioxidants.

    Directory of Open Access Journals (Sweden)

    Yongchao Wang

    Full Text Available DCPTA (2-diethylaminoethyl-3, 4-dichlorophenylether and CCC (2-chloroethyltrimethyl- ammonium chloride have a great effect on maize growth, but applying DCPTA individually can promote the increase of plant height, resulting in the rise of lodging percent. Plant height and lodging percent decrease in CCC-treated plants, but the accumulation of biomass reduce, resulting in yield decrease. Based on the former experiments, the performance of a mixture which contained 40 mg DCPTA and 20 mg CCC as active ingredients per liter of solution, called PCH was tested with applying 40mg/L DCPTA and 20mg/L CCC individually. Grain yield, yield components, internode characters, leaf area per plant, plant height and lodging percent as well as chlorophyll content, chlorophyll fluorescence, enzymatic antioxidants, membranous peroxide and organic osmolyte were analyzed in two years (2011 and 2012, using maize hybrid, Zhengdan 958 (ZD 958 at density of 6.75 plants m-2. CCC, DCPTA and PCH were sprayed on the whole plant leaves at 7 expanded leaves stage and water was used as control. Compared to control, PCH significantly increased grain yield (by 9.53% and 6.68% from 2011 to 2012. CCC significantly decreased kernel number per ear (by 6.78% and 5.69% and thousand kernel weight (TKW (by 8.57% and 6.55% from 2011 to 2012. Kernel number per ear and TKW increased in DCPTA-treated and PCH-treated plants, but showed no significant difference between them. In CCC-treated and PCH-treated plants, internode length and plant height decreased, internode diameter increased, resulting in the significant decline of lodging percent. With DCPTA application, internode diameter increased, but internode length and plant height increased at the same time, resulting in the augment of lodging percent. Bending strength and puncture strength were increased by applying different plant growth regulators (PGRs. In PCH-treated plants, bending strength and puncture strength were greater than other

  4. The Use of chitosan in The Formation of Silver Nanoparticles, Chitosanic Nanoparticles and Fibrous Structures

    Science.gov (United States)

    Abdelgawad, Abdelrahman Mohamed

    Nanoscale materials have attracted much attention in the last two decades due to their unique properties. The size effect attains new chemical and physical properties to these materials. Nanoparticles and nanofiber are major component of nanomaterials and they have heavily investigated in the literature for different applications. Nanoparticles could be produced from both metals as well as polymers. Chitosan, which is a natural polymer, can be used as capping agent in the preparation of metallic nanoparticles and itself, can produce nanoparticles. The utilization of nanoparticles and nanofibers for wound dressing materials is a very popular approach. Acquiring antibacterial properties to the wound dressing materials could be obtained either by formulation of nanomaterials composites or direct chemical modification of the substance. To improve the antibacterial properties of chitosan two approaches were applied. First, is through the formulation of chitosan with silver nanoparticles and the formation of nanofiber mats. In this study, the concepts of green chemistry were applied and silver nanoparticles were prepared in high concentration using chitosan as a capping polymer and glucose as a reducing agent. Nanofiber mats of polyvinyl alcohol/chitosan/silvernanoparticles were produced via electrospinning. The antibacterial activity of these fibers shows bactericidal effect against E. coli at low concentrations of Ag-NPs. In the second approach, direct chemical modification of chitosan was performed by grafting of Iodoacetic acid to the amino group at carbon-2. The chemical structure of chitosan Iodoacetamide derivative (CIA) was confirmed by FTIR and H1-NMR. The derivative was amorphous and water soluble at neutral pH. The minimum inhibitory concentration of CIA, against E. coli, was 400ig/mL and the derivative was bacteriostatic after 4h of treatment. Nanofiber mats of polyvinyl alcohol/chitosan/chitosan Iodoacetamide were produced via electrospinning. The

  5. Comprehending smallholder maize enterprises’ profitability with the current maize marketing system in Zimbabwe: A case of Mazowe district

    Directory of Open Access Journals (Sweden)

    John Basera

    2016-06-01

    Full Text Available Maize enterprise profitability is essential for sustainable maize production in smallholder farming. In Zimbabwe a lot of factors including several policy measures implemented in the past are believed to be influencing current maize profitability trends. Literature to confirm some of the crucial factors is limited especially in the smallholder farming sector. In this study we analyze profitability of smallholder maize farmers in Mazowe District of Zimbabwe. We estimate maize enterprise profitability using gross margin analysis, factors driving profitability using linear regression analysis and the influence of tobacco farming adoption on maize enterprise profitability using propensity score matching. We relied on both primary and secondary data from the study area. Results did not show robust outcomes on maize enterprises profitability. Maize profitability was found to be influenced positively by age of household head and selling produce to private buyers and negatively by fertilizer, chemical, and transport costs. Tobacco farming adoption was found to have a positive influence on maize profitability. Based on the results the study recommends the government through its various programs targeting agricultural development and food security to focus on smallholder maize production and marketing with the aim of improving its profitability.

  6. Preparation of pure chitosan film using ternary solvents and its super absorbency.

    Science.gov (United States)

    Wang, Xuejun; Lou, Tao; Zhao, Wenhua; Song, Guojun

    2016-11-20

    Chemical modification and graft copolymerization were commonly adopted to prepare super absorbent materials. However, physical microstructure of pure chitosan film was optimized to improve the water uptake capacity in this study. Chitosan films with micro-nanostructure were prepared by a ternary solvent system. The optimal process parameters are 1% acetic acid water solution: dioxane: dimethyl sulfoxide=90: 2.5: 7.5 (v/v/v) with chitosan concentration at 1.25% (w/v). The water uptake capacity of the chitosan film prepared under the optimal process parameters was 896g/g. The prepared chitosan films also exhibited high water uptake capacity in response to external stimuli such as temperature, pH and salt. This finding may provide another way for improving the water absorbency. The pure chitosan film may find potential applications especially in the fields of hygienic products and biomedicine due to its super water absorbency and nontoxicity. PMID:27561494

  7. STRATEGY OF MAIZE'S CONCENTRATING TO ADVANTAGE AREAS IN JILIN PROVINCE

    Institute of Scientific and Technical Information of China (English)

    JIANG Hui-ming; GU Li-li

    2003-01-01

    Jilin Province is one of the main grain-producing provinces of China, which has dominant position in maize production, by the view of its advantages in policy, location, breed and market. And after entering WTO,some measures have been taken to enhance maize competitive ability. But there are some difficulties in concentrating production to maize advantaged areas. This paper expounds the basis that Jilin Province becomes the advantage area of maize, analyzes the problems and puts forward the supporting policy. Some strategic measures are proposed,as developing comparable advantages, carrying out the strategy of un-equilibrium development and cultivating advantaged product areas of maize to rapidly improve the international competitive ability and productivity of maize in Jilin Province, cast the agricultural predicament off and promote the agricultural development into a new stage.

  8. Synthesis and evaluation of chitosan-Vitamin C complex

    Directory of Open Access Journals (Sweden)

    Tian X

    2009-01-01

    Full Text Available Chitosan is a biocompatible, biodegradable and non-toxic polysaccharide polymer. It dissolves in water only if the pH is lower than 6.5. To extend its range of application, many water-soluble derivatives have therefore been prepared. In this research, chitosan-vitamin C complex was synthesized and characterized with Fourier transformed infrared spectroscopy, differential scanning calorimetry and 1 H-NMR. The solubility of chitosan-vitamin C complex in distilled water was greatly improved. The ·O2 - scavenging activity of chitosan-vitamin C complex was compared with chitosan and vitamin C by measuring the auto-oxidation rate of pyrogallic acid. Results showed that the scavenging activity on ·O2 - by chitosan-vitamin C complex was stronger than that by CS. At low concentrations (< 0.05 mg/ml, the scavenging activity of chitosan-vitamin C complex was stronger than that of vitamin C, but after certain concentrations (>0.1mg/ml, its scavenging activity was lower than that of vitamin C.

  9. The Importance of Chitosan Films in Food Industry

    Directory of Open Access Journals (Sweden)

    Filiz Uçan

    2013-12-01

    Full Text Available Requirement simple technology, low production costs, lack of polluting effects and reliability in terms of health of it is the most important advantages of edible films. Chitosan that extend the shelf life of food and increase the economic efficiency of packaging materials is one of the new materials used for edible films. Chitosan was obtained by deacetylation of chitin which is the most commonly occurred polymer after cellulose in nature, in shells of arthropods such as crab, shrimp, lobster and in cell walls of some bacteria and fungi. Chitosan has the important bioactive properties such as hemostatic, bacteriostatic, fungistatic, spermicidal, anticarcinogenic, anticholesteremic, antacids, antiulcer, wound and bone healing accelerator and stimulating the immune system. As well as these features, the film forming and barrier properties of its, chitosan is made the ideal material for edible films and coatings in antimicrobial characters. Especially, in the protection of qualities and the improving storage times of fruits and vegetables, have been revealed the potential use of chitosan. The coating food with chitosan films reduces the oxygen partial pressure in the package, maintains temperature with moisture transfer between food and its environment, declines dehydration, delays enzymatic browning in fruits and controls respiration. In addition to, chitosan are also used on issues such as the increasing the natural flavour, setting texture, increasing of the emulsifying effect, stabilization of color and deacidification.

  10. Thermal and magnetic properties of chitosan-iron oxide nanoparticles.

    Science.gov (United States)

    Soares, Paula I P; Machado, Diana; Laia, César; Pereira, Laura C J; Coutinho, Joana T; Ferreira, Isabel M M; Novo, Carlos M M; Borges, João Paulo

    2016-09-20

    Chitosan is a biopolymer widely used for biomedical applications such as drug delivery systems, wound healing, and tissue engineering. Chitosan can be used as coating for other types of materials such as iron oxide nanoparticles, improving its biocompatibility while extending its range of applications. In this work iron oxide nanoparticles (Fe3O4 NPs) produced by chemical precipitation and thermal decomposition and coated with chitosan with different molecular weights were studied. Basic characterization on bare and chitosan-Fe3O4 NPs was performed demonstrating that chitosan does not affect the crystallinity, chemical composition, and superparamagnetic properties of the Fe3O4 NPs, and also the incorporation of Fe3O4 NPs into chitosan nanoparticles increases the later hydrodynamic diameter without compromising its physical and chemical properties. The nano-composite was tested for magnetic hyperthermia by applying an alternating current magnetic field to the samples demonstrating that the heating ability of the Fe3O4 NPs was not significantly affected by chitosan.

  11. Remediation of coal mining wastewaters using chitosan microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Geremias, R.; Pedrosa, R.C.; Benassi, J.C.; Favere, V.T.; Stolberg, J.; Menezes, C.T.B.; Laranjeira, M.C.M. [Federal University of Santa Catarina, Florianopolis (Brazil)

    2003-12-01

    This study aimed to evaluate the potential use of chitosan and chitosan/poly(vinylalcohol) microspheres incorporating tetrasulphonated copper (II) phthalocyanine (CTS / PVA / TCP) in the remediation of coal mining wastewaters. The process was monitored by toxicity tests both before and after adsorption treatments with chitosan and microspheres. Physicochemical parameters, including pH and trace-metal concentration, as well as bioindicators of water pollution were used to that end. Wastewater samples collected from drainage of underground coal mines, decantation pools, and contaminated rivers were scrutinized. Acute toxicity tests were performed using the Brine Shrimp Test (BST) in order to evaluate the remediation efficiency of different treatments. The results showed that the pH of treated wastewater samples were improved to values close to neutrality. Chitosan treatments were also effective in removing trace-metals. Pre-treatment with chitosan followed by microsphere treatment (CTS / PVA / TCP) was more effective in decreasing toxicity than the treatment using only chitosan. This was probably due to the elimination of pollutants other than trace-metals. Thus, the use of chitosan and microspheres is an adequate alternative towards remediation of water pollution from coal mining.

  12. Thermal and magnetic properties of chitosan-iron oxide nanoparticles.

    Science.gov (United States)

    Soares, Paula I P; Machado, Diana; Laia, César; Pereira, Laura C J; Coutinho, Joana T; Ferreira, Isabel M M; Novo, Carlos M M; Borges, João Paulo

    2016-09-20

    Chitosan is a biopolymer widely used for biomedical applications such as drug delivery systems, wound healing, and tissue engineering. Chitosan can be used as coating for other types of materials such as iron oxide nanoparticles, improving its biocompatibility while extending its range of applications. In this work iron oxide nanoparticles (Fe3O4 NPs) produced by chemical precipitation and thermal decomposition and coated with chitosan with different molecular weights were studied. Basic characterization on bare and chitosan-Fe3O4 NPs was performed demonstrating that chitosan does not affect the crystallinity, chemical composition, and superparamagnetic properties of the Fe3O4 NPs, and also the incorporation of Fe3O4 NPs into chitosan nanoparticles increases the later hydrodynamic diameter without compromising its physical and chemical properties. The nano-composite was tested for magnetic hyperthermia by applying an alternating current magnetic field to the samples demonstrating that the heating ability of the Fe3O4 NPs was not significantly affected by chitosan. PMID:27261762

  13. PLA/chitosan/keratin composites for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Tanase, Constantin Edi, E-mail: etanase@live.com [Faculty of Medical Bioengineering, ‘Grigore T. Popa’ University of Medicine and Pharmacy, 9-13 Kogalniceanu Street, 700454 Iasi (Romania); Spiridon, Iuliana [“Petru Poni” Institute of Macromolecular Chemistry, 41A Grigore Ghica Voda Alley, 700487 Iasi (Romania)

    2014-07-01

    Novel composites based on PLA, chitosan and keratin was obtained via blend preparation. The goal of this contribution was to evaluate mechanical and in vitro behavior of the composites. The results point out composites with improved Young modulus and decreased tensile strength, significant increase in hardness (compared to PLA) and a good uptake of the surface properties. Biological assessments using human osteosarcoma cell line on these composites indicate a good viability/proliferation outcome. Hence preliminary results regarding mechanical behavior and in vitro osteoblast response suggest that these composites might have prospective application in medical field. - Highlights: • PLA, chitosan and keratin composites are prepared by blend preparation. • PLA, chitosan and keratin composites present improved mechanical properties and water uptake compare to PLA. • PLA, chitosan and keratin composites present good in vitro behavior.

  14. Synthesis and optimization of chitosan nanoparticles: Potential applications in nanomedicine and biomedical engineering

    OpenAIRE

    Ghadi, Arezou; Mahjoub, Soleiman; Tabandeh, Fatemeh; Talebnia, Farid

    2014-01-01

    Background: Chitosan nanoparticles have become of great interest for nanomedicine, biomedical engineering and development of new therapeutic drug release systems with improved bioavailability, increased specificity and sensitivity, and reduced pharmacological toxicity. The aim of the present study was to synthesis and optimize of the chitosan nanoparticles for industrial and biomedical applications. Methods: Fe3O4 was synthesized and optimized as magnetic core nanoparticles and then chitosan ...

  15. THE DEVELOPMENT OF CHITOSAN NANOPARTICLES FROM HIBISCUS SABDARIFFA L CALYX EXTRACT FROM INDONESIA AND THAILAND

    OpenAIRE

    Nurkhasanah*, Tedjo Yuwono, Laela Hayu Nurani, Muhammad Ikhwan Rizki and Krisana Kraisintu

    2015-01-01

    Rosella (Hibiscus sabdariffa L) calyx has been reported to have an antioxidant activity. Antocyanidin is the major compound of rosella and has low bioavailability as an ionic form. Rosella extract is an ucceptable due to high acidity. Development of chitosan nanoparticle from Hibiscus sabdariffa extract were expected to improve the bioavailability and the acidity problem. We studied the optimum pH and composition ratios of chitosan, extract and tripolyphosphate (TPP) to develop chitosan-nanop...

  16. Applications of chitosan nanoparticles in drug delivery.

    Science.gov (United States)

    Tajmir-Riahi, H A; Nafisi, Sh; Sanyakamdhorn, S; Agudelo, D; Chanphai, P

    2014-01-01

    We have reviewed the binding affinities of several antitumor drugs doxorubicin (Dox), N-(trifluoroacetyl) doxorubicin (FDox), tamoxifen (Tam), 4-hydroxytamoxifen (4-Hydroxytam), and endoxifen (Endox) with chitosan nanoparticles of different sizes (chitosan-15, chitosan-100, and chitosan-200 KD) in order to evaluate the efficacy of chitosan nanocarriers in drug delivery systems. Spectroscopic and molecular modeling studies showed the binding sites and the stability of drug-polymer complexes. Drug-chitosan complexation occurred via hydrophobic and hydrophilic contacts as well as H-bonding network. Chitosan-100 KD was the more effective drug carrier than the chitosan-15 and chitosan-200 KD. PMID:24567139

  17. Effect Of Chitosan Application On The Performance Of Lentil Genotypes Under Rainfed Conditions

    Directory of Open Access Journals (Sweden)

    Janmohammadi Mohsen

    2014-12-01

    Full Text Available In the current study, influences of chitosan solutions on morphological characteristics, growth and yield components of lentil (Lens culinaris Med. under rainfed conditions have been investigated. A field experiment was conducted in the Northwest of Iran using a split-plot experiment based on a completely randomized design with three replications. The response of twelve genotypes with different origins to chitosan application at the sowing (seed soaking, vegetative and reproductive stage (spraying chitosan onto leaves was evaluated. Results revealed that chitosan application could significantly improve the number of pods per plant, 100-seed weight, grain yield per plant and harvest index in comparison to control plants. The comparison of yield components between chitosan treatments showed that spraying chitosan during the reproductive stage was more efficient than in other stages. However, the responses of the number of pods per plants and grain yield per plants to chitosan treatments were significantly different among the genotypes. Although the highest grain yield was recorded in the 78S 26013 genotype (from Jordan, its response to chitosan treatments was different from the other genotypes and showed the best performance in plants obtained from seed soaked in chitosan solutions. We suggest that the application of chitosan as an agronomic management strategy be further investigated for an efficient technique to induce resistance in lentil plants against biotic and drought stress in semi-arid regions.

  18. 10 Reasons to be Tantalized by the B73 Maize Genome

    OpenAIRE

    Fusheng Wei; Jianwei Zhang; Shiguo Zhou; Ruifeng He; Mary Schaeffer; Kristi Collura; David Kudrna; Faga, Ben P.; Marina Wissotski; Wolfgang Golser; Rock, Susan M.; Graves, Tina A.; Fulton, Robert S.; Ed Coe; Patrick S Schnable

    2009-01-01

    Maize is a major cereal crop and an important model system for basic biological research. Knowledge gained from maize research can also be used to genetically improve its grass relatives such as sorghum, wheat, and rice. The primary objective of the Maize Genome Sequencing Consortium (MGSC) was to generate a reference genome sequence that was integrated with both the physical and genetic maps. Using a previously published integrated genetic and physical map, combined with in-coming maize geno...

  19. Chitosan-film enhanced chitosan nerve guides for long-distance regeneration of peripheral nerves.

    Science.gov (United States)

    Meyer, Cora; Stenberg, Lena; Gonzalez-Perez, Francisco; Wrobel, Sandra; Ronchi, Giulia; Udina, Esther; Suganuma, Seigo; Geuna, Stefano; Navarro, Xavier; Dahlin, Lars B; Grothe, Claudia; Haastert-Talini, Kirsten

    2016-01-01

    Biosynthetic nerve grafts are developed in order to complement or replace autologous nerve grafts for peripheral nerve reconstruction. Artificial nerve guides currently approved for clinical use are not widely applied in reconstructive surgery as they still have limitations especially when it comes to critical distance repair. Here we report a comprehensive analysis of fine-tuned chitosan nerve guides (CNGs) enhanced by introduction of a longitudinal chitosan film to reconstruct critical length 15 mm sciatic nerve defects in adult healthy Wistar or diabetic Goto-Kakizaki rats. Short and long term investigations demonstrated that the CNGs enhanced by the guiding structure of the introduced chitosan film significantly improved functional and morphological results of nerve regeneration in comparison to simple hollow CNGs. Importantly, this was detectable both in healthy and in diabetic rats (short term) and the regeneration outcome almost reached the outcome after autologous nerve grafting (long term). Hollow CNGs provide properties likely leading to a wider clinical acceptance than other artificial nerve guides and their performance can be increased by simple introduction of a chitosan film with the same advantageous properties. Therefore, the chitosan film enhanced CNGs represent a new generation medical device for peripheral nerve reconstruction. PMID:26517563

  20. Synthesis of conjugated chitosan and its effect on drug permeation from transdermal patches

    Directory of Open Access Journals (Sweden)

    B K Satheeshababu

    2013-01-01

    Full Text Available The aim of this study was to synthesis the conjugated chitosan by covalent attachment of thiol moieties to the cationic polymer, mediated by a carbodiimide to improve permeation properties of chitosan. Thioglycolic acid was covalently attached to chitosan by the formation of amide bonds between the primary amino groups of the polymer and the carboxylic acid groups of thioglycolic acid. Hence, these polymers are called as thiomers or thiolated polymers. Conjugation of chitosan was confirmed by Fourier transform-infrared and differential scanning calorimetric analysis. Matrix type transdermal patches of carvedilol were prepared using the different proportions of chitosan and chitosan-thioglycolic acid conjugates (2:0, 1.7:0.3, 1.4:0.6, 1:1, 0.6:1.4 and 0.3:1.7 by solvent casting technique. Prepared matrix type patches were evaluated for their physicochemical characterization followed by in vitro evaluation. Selected formulations were subjected for their ex vivo studies on Wistar albino rat skin and human cadaver skin using the modified Franz diffusion cell. As the proportion of conjugated chitosan increased, the transdermal patches showed increased drug permeation. The mechanism of drug release was found to be nonFickian profiles. The present study concludes that the transdermal patches of carvedilol using conjugated chitosan with different proportions of chitosan were successfully developed to provide improved drug permeation. The transdermal patches can be a good approach to improve drug bioavailability by bypassing the extensive hepatic first-pass metabolism of the drug.

  1. Influence of Seed Coating Formulations on Maize Production

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Effects of four coating formulations on maize production were studied. The results showec that all coating formulations had some effects on improving maize seedlings, strengthening the resistance againt diseases and pests and increasing the yields in dtifferent degrees, especially Paxil which increased the com yield by 12.0%, significantly higher than the control.

  2. Utilization of chitosan as an antimicrobial agent for pasteurized palm sap (Borassus flabellifer Linn.) during storage.

    Science.gov (United States)

    Naknean, Phisut; Jutasukosol, Keawta; Mankit, Theerarat

    2015-02-01

    The objective of this research was to assess the potential of chitosan for improvement the quality of pasteurized palm sap during storage. First, the effect of chitosan content on sensory attributes was investigated to select suitable concentration of chitosan for further study. Fresh palm sap was enriched with chitosan at various concentrations (0-2 g/L) and pasteurized at 80 °C for 10 min, consequently evaluated by consumers. It was found that samples added chitosan in the range of 0-1.00 g/L were considered acceptable. Thus, the addition chitosan in the concentration of 0-1.00 g/L was chosen for further study. The sample without chitosan addition was used as a control sample. Each selected sample was determined for their qualities during storage at 1 week interval. It was found that lightness and transmittance values of all samples tended to increase during storage. Lower PPO and invertase activity were observed in all chitosan-treated samples compared to control sample. Chitosan could minimize the loss of sucrose and the increase in glucose and fructose content during storage. In addition, an increase in chitosan concentration resulted in the increase in DPPH radical scavenging activity. Furthermore, the addition of chitosan could retard the development of microorganism during storage as demonstrated by lower microbial loads compared to control sample. It can be concluded that a combination of pasteurization with chitosan addition (0.50 g/L) and low temperature storage could preserve palm sap for approximately 6 weeks. Thus, the incorporation of chitosan in palm sap could be used as an alternative way to extend shelf life of pasteurized palm sap. PMID:25694681

  3. Improvement of grape and wine phenolic content by foliar application to grapevine of three different elicitors: Methyl jasmonate, chitosan, and yeast extract.

    Science.gov (United States)

    Portu, Javier; López, Rosa; Baroja, Elisa; Santamaría, Pilar; Garde-Cerdán, Teresa

    2016-06-15

    Phenolic compounds play a key role in grape and wine organoleptic properties, being therefore a key parameter in wine quality. Elicitor application constitutes an interesting field of research since it is indirectly involved in the accumulation of phenolic compounds. The aim of this study was to compare the effect of the application of three different elicitors on both grape and wine phenolic content. Methyl jasmonate, chitosan, and a commercial yeast extract were applied to the canopy at veraison and one week later. Results showed that foliar treatments carried out with methyl jasmonate and yeast extract achieved the best results, increasing grape and wine anthocyanin content when compared to the control. Moreover, the application of the yeast elicitor also enhanced grape stilbene content. In contrast, the chitosan treatment did not have a substantial impact on the phenolic compounds. The results of this study indicate that methyl jasmonate and yeast extract applications could be a simple practice to increase grape and wine phenolic content. PMID:26868568

  4. Modification of Cellulose Products by the Use of Chitosan and Chitosan-Alginate Nano-Particles

    Directory of Open Access Journals (Sweden)

    Brzoza-Malczewska Kinga

    2016-03-01

    Full Text Available Aim of the presented research was the improvement of fibrous cellulosic products for uses in hygiene and medical sectors. Nano-particles of bioactive polysaccharides were imparted to cellulosic fibrous products to modify their properties: physical–chemical like absorption, biological like antibacterial and antifungal activity, and mechanical. Fibrous materials like dressing gauze, wood-wool, and hygiene tissues were modified by the addition of chitosan and chitosan-alginate nano-particles. Padding and freeze-drying was applied in the coating of the fibrous materials with the nano-sized polymers.

  5. FINANCIAL AND RISK ANALYSIS OF MAIZE TECHNOLOGY IN ETHIOPIA, BASED ON CERES-MAIZE MODEL RESULTS

    OpenAIRE

    Crawford, Eric W.; Howard, Julie A.; Kelly, Valerie A.

    2000-01-01

    This paper presents a financial and risk analysis of improved versus traditional maize production technology in Ethiopia, based on yields simulated with the CERES-Maize crop growth model (Schulthess and Ward, 2000). The purpose is to analyze the potential performance of the SG2000/Ministry of Agriculture program technology under less favorable meteorological conditions (rainfall level and distribution), and in areas with lower agroecological potential than those covered by the SG2000/MOA prog...

  6. Preparation and characterization of chitosan/nano-hydroxyapatite composite used as bone substitute materials

    Institute of Scientific and Technical Information of China (English)

    Zhang Li; Li Yubao; Zhou Gang; Wu Lan; Mu Yuanhua; Yang Zheng

    2007-01-01

    Chitosan/nano-hydroxyapatite composites with different weight ratios were prepared through a co-precipitation method using Ca(OH)2, H3PO4 and chitosan as starting materials. The properties of these composites were characterized by means of TEM, IR, XRD, TGA, bum-out tests and universal matertial testing machine. The results showed that the HA synthesized here was poorly crystalline carbonated nanometer crystals and dispersed uniformly in chitosan phase and there was no phase-separation between the two phases. The addition of n-HA resulted in a decrease of decomposing temperature of chitosan. Because of the interactions between chitosan and n-HA, the mechanical properties of these composites were improved, and the maximum value of the compressive strength was measured to be about 120MPa corresponding to the chitosan/n-HA composite with a weight ratio of 30/70.

  7. [Characteristics of farmland eco-environment at the intercropping stage of maize intercropped with winter wheat and their effects on seedling growth of summer maize].

    Science.gov (United States)

    Zhu, Yuan-gang; Li, Hong-jie; Cui, Xin-yan; Jia, Chun-lan; Yang, Jin-sheng; Liu, Shao-kun; Zhang, Ji-wang; Dong, Shu-ting

    2015-07-01

    To study the farmland eco-environment of intercropping maize with wheat at the intercropping stage and its influence on maize seedling growth, two summer maize cultivars, Zhengdan 958 and Denghai 661, were either intercropped with wheat or directly seeded. The result demonstrated that there was little difference for the soil water content of the farmland between the two cultivation methods. The highest soil temperature of intercropped maize was 4.8-5.2 °C lower than the soil temperature of directly-seeded maize, and the lowest temperature of the intercropped maize was 1.4-1.7 °C lower. But, the temperatures for both planting methods met the requirement for seed germination. Light intensity on the ground surface of the intercropped maize was 4.4%-10.6% less than natural light, and insufficient light was the main reason for the weak and late seedling. Compared to the directly-seeded maize, the speeds of seed germination and accumulation of dry matters of the intercropped maize were relatively slow. On the whole, the seedling of intercropped maize was not strong, which presented small leaves, short height and low chlorophyll content. The restraint on the growth of intercropped maize was enhanced with the extension of intercropping period. For farm planting, direct-seeding could improve the seed germination and seedling growth of summer maize. PMID:26710624

  8. Chitosan in Plant Protection

    Directory of Open Access Journals (Sweden)

    Abdelbasset El Hadrami

    2010-03-01

    Full Text Available Chitin and chitosan are naturally-occurring compounds that have potential in agriculture with regard to controlling plant diseases. These molecules were shown to display toxicity and inhibit fungal growth and development. They were reported to be active against viruses, bacteria and other pests. Fragments from chitin and chitosan are known to have eliciting activities leading to a variety of defense responses in host plants in response to microbial infections, including the accumulation of phytoalexins, pathogen-related (PR proteins and proteinase inhibitors, lignin synthesis, and callose formation. Based on these and other proprieties that help strengthen host plant defenses, interest has been growing in using them in agricultural systems to reduce the negative impact of diseases on yield and quality of crops. This review recapitulates the properties and uses of chitin, chitosan, and their derivatives, and will focus on their applications and mechanisms of action during plant-pathogen interactions.

  9. Preparation of alginate-chitosan fibers with potential biomedical applications.

    Science.gov (United States)

    Sibaja, Bernal; Culbertson, Edward; Marshall, Patrick; Boy, Ramiz; Broughton, Roy M; Solano, Alejandro Aguilar; Esquivel, Marianelly; Parker, Jennifer; De La Fuente, Leonardo; Auad, Maria L

    2015-12-10

    The preparation of alginate-chitosan fibers, through wet spinning technique, as well as the study of their properties as a function of chitosan's molecular weight and retention time in the coagulation bath, is presented and discussed in this work. Scanning electron microscopy (SEM) revealed that the fibers presented irregular and rough surfaces, with a grooved and heavily striated morphology distributed throughout the structure. Dynamic mechanical analysis (DMA) showed that, with the exception of elongation at break, the incorporation of chitosan into the fibers improved their tensile properties. The in vitro release profile of sulfathiazole as a function of chitosan's molecular weight indicated that the fibers are viable carriers of drugs. Kinetic models showed that the release of the model drug is first-order, and the release mechanism is governed by the Korsmeyer-Peppas model. Likewise, fibers loaded with sulfathiazole showed excellent inhibition of Escherichia coli growth after an incubation time of 24h at 37 °C. PMID:26428163

  10. Use of chitosan to prolong mozzarella cheese shelf life.

    Science.gov (United States)

    Altieri, C; Scrocco, C; Sinigaglia, M; Del Nobile, M A

    2005-08-01

    This study was undertaken to evaluate the feasibility of using chitosan, a natural antimicrobial substance, to improve the preservation of a very perishable cheese. The effectiveness of chitosan to inhibit the growth of spoilage microorganisms in Mozzarella cheese was studied during refrigerated storage. A lactic acid/chitosan solution was added directly to the starter used for Mozzarella cheese manufacturing. Mozzarella cheese samples were stored at 4 degrees C for about 10 d and microbial populations as well as the pH were monitored. Results demonstrated that chitosan inhibited the growth of some spoilage microorganisms such as coliforms, whereas it did not influence the growth of other microorganisms, such as Micrococcaceae, and lightly stimulated lactic acid bacteria.

  11. A review on chitosan-based adsorptive membranes.

    Science.gov (United States)

    Salehi, Ehsan; Daraei, Parisa; Arabi Shamsabadi, Ahmad

    2016-11-01

    Membrane adsorbents have emerged as powerful and attractive tools for the removal of hazardous materials such as dyes and heavy metal ions, mainly in trace amounts, from water resources. Among membrane adsorbents, those prepared from or modified with chitosan biopolymer and its derivatives are cases of interest because of chitosan advantages including biocompatibility, biodegradability, nontoxicity, reactivity, film and fiber forming capacity and favorable hydrophilicity. This review is oriented to provide a framework for better insight into fabrication methods and applications of chitosan-based adsorptive membranes. Critical aspects including thermokinetic analyses of adsorption and regeneration capacity of the membrane adsorbents have been also overviewed. Future of chitosan-based adsorptive membranes might include efforts for the improvement of mechanical stability and reusability and also most targeted application of appropriate copolymers as well as nanostructures in preparing high performance adsorptive membranes. PMID:27516289

  12. Bt maize and integrated pest management--a European perspective.

    Science.gov (United States)

    Meissle, Michael; Romeis, Jörg; Bigler, Franz

    2011-09-01

    The European corn borer (Ostrinia nubilalis), the Mediterranean corn borer (Sesamia nonagrioides) and the western corn rootworm (Diabrotica virgifera virgifera) are the main arthropod pests in European maize production. Practised pest control includes chemical control, biological control and cultural control such as ploughing and crop rotation. A pest control option that is available since 1996 is maize varieties that are genetically engineered (GE) to produce insecticidal compounds. GE maize varieties available today express one or several genes from Bacillus thuringiensis (Bt) that target corn borers or corn rootworms. Incentives to growing Bt maize are simplified farm operations, high pest control efficiency, improved grain quality and ecological benefits. Limitations include the risk of resistance evolution in target pest populations, risk of secondary pest outbreaks and increased administration to comply with licence agreements. Growers willing to plant Bt maize in the European Union (EU) often face the problem that authorisation is denied. Only one Bt maize transformation event (MON810) is currently authorised for commercial cultivation, and some national authorities have banned cultivation. Spain is the only EU member state where Bt maize adoption levels are currently delivering farm income gains near full potential levels. In an integrated pest management (IPM) context, Bt maize can be regarded as a preventive (host plant resistance) or a responsive pest control measure. In any case, Bt maize is a highly specific tool that efficiently controls the main pests and allows combination with other preventive or responsive measures to solve other agricultural problems including those with secondary pests.

  13. Inhibition of Inositol-1-phosphate Synthetase in Mycobacterium Tuberculosis by Chitosan-antisense Nanoparticles

    Institute of Scientific and Technical Information of China (English)

    LI Yuanyuan; CHEN Zhifei; ZHANG Hongling; LI Xiaobo; SHEN Jie; LU Shi; XU Shunqing

    2009-01-01

    Oligodeoxynucleotides (ODNs) were combined with the biodegradable polymer chitosan to form chitosan-ODN nanoparticles by complex coacervation, in order to improve the sta-bility and intracellular penetration. The diameter of the nanoparticles was light strength size and ranged between 60 and 219 nm with a mean value of 132 nm, while zeta potential was between +12 and + 20 mV at pH 5.5. The chitosan-ODN nanoparticles could partially protect the encapsulated ODN from nuclease degradation. Moreover, chitosan-ODN nanoparticles were much more effective in inhibiting the proliferation of M.tuberculosis than free ODN.

  14. Linear and Branched Chitosan Oligomers as Delivery Systems for pDNA and siRNA In Vitro and In Vivo

    OpenAIRE

    Issa, Mohamed Mahmoud

    2006-01-01

    In this thesis, chitosan, a biocompatible polysaccharide that has been approved as a food additive was selected as a platform for the development of safe, efficient non-viral gene delivery systems to mammalian cells. Previously, chitosan-based gene formulations had been generally associated with high molecular weight chitosans, which were poorly characterised in terms of molecular weight distribution and degree of acetylation. Therefore, in order to improve the properties of chitosan-based ge...

  15. Antitumour Acitivty of Chitosan Hydrogen Selenites

    Institute of Scientific and Technical Information of China (English)

    CaiQinQIN; XiaoHaiGAO; 等

    2002-01-01

    Chitosans reacted with selenious acid to prepare chitosan hydrogen selenites, which were found to be growth-inhibitory against sarcoma 180 solid tumor. The results indicated that the activity also depended on the molecular weight of chitosan supports.

  16. Antitumour Activity of Chitosan Hydrogen Selenites

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Chitosans reacted with selenious acid to prepare chitosan hydrogen selenites, which were found to be growth-inhibitory against sarcoma 180 solid tumor. The results indicated that the activity also depended on the molecular weight of chitosan supports.

  17. N-carboxyethyl chitosan fibers prepared as potential use in tissue engineering.

    Science.gov (United States)

    Yang, Shuoshuo; Dong, Qi; Yang, Hongjun; Liu, Xin; Gu, Shaojin; Zhou, Yingshan; Xu, Weilin

    2016-01-01

    To improve the hydrophilicity of chitosan fiber, N-carboxyethyl chitosan fiber was prepared through Michael addition between chitosan fiber with acrylic acid. The structure was studied by (1)H NMR. The degree of N-substitution, measured via (1)H NMR, was easily varied from 0.10 to 0.51 by varying the molar ratio of acrylic acid to chitosan. Series of properties of N-carboxyethyl chitosan fiber including mechanical property, crystallinity, thermal property and in vitro degradation were investigated by Instron machine, X-ray diffraction and differential scanning calorimetry and thermogravimetric analysis, respectively. The results showed that, introducing the carboxyethyl group into the backbone chain of chitosan fiber destroyed the intra/intermolecular hydrogen bonding, leading to loss of the intra/intermolecular hydrogen bonding and improvement of hydrophilicity. Indirect cytotoxicity assessment of carboxyethyl chitosan fibers was investigated using a L929 cell line. And the obtained results clearly suggested that N-carboxyethyl chitosan fiber was nontoxic to L929 cells. The N-carboxyethyl chitosan fibers are potential as tissue engineering scaffolds. PMID:26522245

  18. Isolation and Identification of Indigenous Plant Growth Promoting Rhizobacteria from Himalayan Region of Kashmir and their Effect on Improving Growth and Nutrient Contents of Maize (Zea Mays L.)

    OpenAIRE

    Mahwish eZahid

    2015-01-01

    IIntroduction and exploitation of plant growth promoting rhizobacteria (PGPR) in agro-ecosystems enhance plant-microbes interactions that may affect ecosystems sustainability, agricultural productivity and environmental quality. The present study was conducted to isolate and identify PGPRs associated with maize (Zea mays L.) from twenty sites of Himalayan region of Hajira-Rawalakot, Azad Jammu and Kashmir (AJK), Pakistan. A total of one hundred isolates were isolated from these sites, out of ...

  19. Isolation and identification of indigenous plant growth promoting rhizobacteria from Himalayan region of Kashmir and their effect on improving growth and nutrient contents of maize (Zea mays L.)

    OpenAIRE

    Zahid, Mahwish; Abbasi, M. Kaleem; Hameed, Sohail; Rahim, Nasir

    2015-01-01

    Introduction and exploitation of plant growth promoting rhizobacteria (PGPR) in agro-ecosystems enhance plant–microbes interactions that may affect ecosystems sustainability, agricultural productivity, and environmental quality. The present study was conducted to isolate and identify PGPRs associated with maize (Zea mays L.) from twenty sites of Himalayan region of Hajira-Rawalakot, Azad Jammu and Kashmir (AJK), Pakistan. A total of 100 isolates were isolated from these sites, out of which ei...

  20. Improvement of chitosan derivatization for the immobilization of bacillus circulans β-galactosidase and its further application in galacto-oligosaccharide synthesis.

    Science.gov (United States)

    Urrutia, Paulina; Bernal, Claudia; Wilson, Lorena; Illanes, Andrés

    2014-10-15

    Chitosan was derivatized by two methodologies to design a robust biocatalyst of immobilized Bacillus circulans β-galactosidase from a low-cost support for its further application in the synthesis of galacto-oligosaccharides (GOS). In the first one, chitosan was derivatized by cross-linking with glutaraldehyde and activated with epichlorohydrin; in the second one, cross-linking and activation were done with epichlorohydrin in a two-step process, favoring first support cross-linking and then support functionalization (C-EPI-EPI). Epoxy groups were hydrolyzed and oxidized, obtaining two supports activated with different aldehyde concentrations (100-250 μmol/g). The expressed activity and stability of the immobilized biocatalysts varied according to the derivatization methodology, showing that both the cross-linking agent and the activation degree are key parameters in the final biocatalyst performance. The best compromise between expressed activity and thermal stability was obtained using C-EPI-EPI with 200 μmol of aldehyde groups per gram of support. The immobilization conditions were optimized, obtaining a biocatalyst with 280 IU/g, immobilization yields in terms of activity and protein of 17.3 ± 0.4 and 61.5 ± 3.9%, respectively, and a high thermal stability, with a half-life of 449 times the value of the soluble enzyme. The biocatalyst was applied to the synthesis of GOS in repeated batch operation without affecting the product composition. Four successive batches were required for obtaining a cumulative specific productivity higher than the one obtained with the soluble enzyme.

  1. Comparison of chitosan nanoparticles and chitosan hydrogels for vaccine delivery

    DEFF Research Database (Denmark)

    Gordon, Sarah; Saupe, Anne; McBurney, Warren;

    2008-01-01

    . The immunostimulatory capacity of these vaccine delivery systems was assessed in-vitro and in-vivo. Particle sizing measurements and SEM images showed that optimised OVA-loaded CNP had a size of approximately 200 nm, a polydispersity index ...In this work the potential of chitosan nanoparticles (CNP) and thermosensitive chitosan hydrogels as particulate and sustained release vaccine delivery systems was investigated. CNP and chitosan hydrogels were prepared, loaded with the model protein antigen ovalbumin (OVA) and characterised...

  2. Thiolated chitosan nanoparticles: transfection study in the Caco-2 differentiated cell culture

    International Nuclear Information System (INIS)

    The aim of this study was to monitor the expression of secreted protein in differentiated Caco-2 cells after transfection with nanoparticles, in order to improve gene delivery. Based on unmodified chitosan and thiolated chitosan conjugates, nanoparticles with the gene reporter pSEAP (recombinant Secreted Alkaline Phosphatase) were generated at pH 4.0. Transfection studies of thiolated chitosan in Caco-2 cells during the exponential growth phase and differentiation growth phase of the cells led to a 5.0-fold and 2.0-fold increase in protein expression when compared to unmodified chitosan nanoparticles. The mean particle size for both unmodified chitosan and cross-linked thiolated chitosan nanoparticles is 212.2 ± 86 and 113.6 ± 40 nm, respectively. The zeta potential of nanoparticles was determined to be 7.9 ± 0.38 mV for unmodified chitosan nanoparticles and 4.3 ± 0.74 mV for cross-linked thiolated chitosan nanoparticles. Red blood cell lysis evaluation was used to evaluate the membrane damaging properties of unmodified and thiolated chitosan nanoparticles and led to 4.61 ± 0.36% and 2.29 ± 0.25% lysis, respectively. Additionally, cross-linked thiolated chitosan nanoparticles were found to exhibit higher stability toward degradation in gastric juices. Furthermore the reversible effect of thiolated chitosan on barrier properties was monitored by measuring the transepithelial electrical resistance (TEER) and is supported by immunohistochemical staining for the tight junction protein claudin. According to these results cross-linked thiolated chitosan nanoparticles have the potential to be used as a non-viral vector system for gene therapy

  3. Thiolated chitosan nanoparticles: transfection study in the Caco-2 differentiated cell culture

    Science.gov (United States)

    Martien, Ronny; Loretz, Brigitta; Sandbichler, Adolf Michael; Bernkop Schnürch, Andreas

    2008-01-01

    The aim of this study was to monitor the expression of secreted protein in differentiated Caco-2 cells after transfection with nanoparticles, in order to improve gene delivery. Based on unmodified chitosan and thiolated chitosan conjugates, nanoparticles with the gene reporter pSEAP (recombinant Secreted Alkaline Phosphatase) were generated at pH 4.0. Transfection studies of thiolated chitosan in Caco-2 cells during the exponential growth phase and differentiation growth phase of the cells led to a 5.0-fold and 2.0-fold increase in protein expression when compared to unmodified chitosan nanoparticles. The mean particle size for both unmodified chitosan and cross-linked thiolated chitosan nanoparticles is 212.2 ± 86 and 113.6 ± 40 nm, respectively. The zeta potential of nanoparticles was determined to be 7.9 ± 0.38 mV for unmodified chitosan nanoparticles and 4.3 ± 0.74 mV for cross-linked thiolated chitosan nanoparticles. Red blood cell lysis evaluation was used to evaluate the membrane damaging properties of unmodified and thiolated chitosan nanoparticles and led to 4.61 ± 0.36% and 2.29 ± 0.25% lysis, respectively. Additionally, cross-linked thiolated chitosan nanoparticles were found to exhibit higher stability toward degradation in gastric juices. Furthermore the reversible effect of thiolated chitosan on barrier properties was monitored by measuring the transepithelial electrical resistance (TEER) and is supported by immunohistochemical staining for the tight junction protein claudin. According to these results cross-linked thiolated chitosan nanoparticles have the potential to be used as a non-viral vector system for gene therapy.

  4. Chitosan and chemically modified chitosan beads for acid dyes sorption

    Institute of Scientific and Technical Information of China (English)

    AZLAN Kamari; WAN SAIME Wan Ngah; LAI KEN Liew

    2009-01-01

    The capabilities of chitosan and chitosan-EGDE (ethylene glycol diglycidyl ether) beads for removing Acid Red 37 (AR 37) and Acid Blue 25 (AB 25) from aqueous solution were examined. Chitosan beads were cross-linked with EGDE to enhance its chemical resistance and mechanical strength. Experiments were performed as a function of pH, agitation period and concentration of AR 37 and AB 25. It was shown that the adsorption capacities of chitosan were comparatively higher than chitosan-EGDE for both acid dyes. This is mainly because cross-linking using EGDE reduces the major adsorption sites -NH3+ on chitosan. Langmuir isotherm model showed best conformity compared to Freundlich and BET. The kinetic experimental data agreed very well to the pseudo second-order kinetic model. The desorption study revealed that after three cycles of adsorption and desorption by NaOH and HCl, both adsorbents retained their promising adsorption abilities. FT-IR analysis proved that the adsorption of acid dyes onto chitosan-based adsorbents was a physical adsorption. Results also showed that chitosan and chitosan-EGDE beads were favourable adsorbers and could be employed as low-cost alternatives for the removal of acid dyes in wastewater treatment.

  5. Chitosan nanoparticle based delivery systems for sustainable agriculture.

    Science.gov (United States)

    Kashyap, Prem Lal; Xiang, Xu; Heiden, Patricia

    2015-01-01

    Development of technologies that improve food productivity without any adverse impact on the ecosystem is the need of hour. In this context, development of controlled delivery systems for slow and sustained release of agrochemicals or genetic materials is crucial. Chitosan has emerged as a valuable carrier for controlled delivery of agrochemicals and genetic materials because of its proven biocompatibility, biodegradability, non-toxicity, and adsorption abilities. The major advantages of encapsulating agrochemicals and genetic material in a chitosan matrix include its ability to function as a protective reservoir for the active ingredients, protecting the ingredients from the surrounding environment while they are in the chitosan domain, and then controlling their release, allowing them to serve as efficient gene delivery systems for plant transformation or controlled release of pesticides. Despite the great progress in the use of chitosan in the area of medical and pharmaceutical sciences, there is still a wide knowledge gap regarding the potential application of chitosan for encapsulation of active ingredients in agriculture. Hence, the present article describes the current status of chitosan nanoparticle-based delivery systems in agriculture, and to highlight challenges that need to be overcome.

  6. Conductivity enhancement via chemical modification of chitosan based green polymer electrolyte

    International Nuclear Information System (INIS)

    The potential of carboxymethyl chitosan as a green polymer electrolyte has been explored. Chitosan produced from partial deacetylation of chitin was reacted with monochloroacetic acid to form carboxymethyl chitosan. A green polymer electrolyte based chitosan and carboxymethyl chitosan was prepared by solution-casting technique. The powder and films were characterized by reflection Fourier transform infrared (ATR-FTIR) spectroscopy, 1H nuclear magnetic resonance, elemental analysis and X-ray diffraction, electrochemical impedance spectroscopy, and scanning electron microscopy. The shift of wavenumber that represents hydroxyl and amine stretching confirmed the polymer solvent complex formation. The XRD spectra results show that chemical modification of chitosan has improved amorphous properties of chitosan. The ionic conductivity was found to increase by two magnitudes higher with the chemical modification of chitosan. The highest conductivity achieved was 3.6 × 10−6 S cm−1 for carboxymethyl chitosan at room temperature and 3.7 × 10−4 S cm−1 at 60 °C

  7. Physico-chemical/biological properties of tripolyphosphate cross-linked chitosan based nanofibers

    Energy Technology Data Exchange (ETDEWEB)

    Sarkar, Soumi Dey [School of Medical Science and Technology, Indian Institute of Technology Kharagpur, Kharagpur-721302 (India); Farrugia, Brooke L.; Dargaville, Tim R. [Institute of Health and Biomedical Innovation, Queensland University of Technology, Kelvin Groove, Queensland-4059 (Australia); Dhara, Santanu, E-mail: sdhara@smst.iitkgp.ernet.in [School of Medical Science and Technology, Indian Institute of Technology Kharagpur, Kharagpur-721302 (India)

    2013-04-01

    In this study, chitosan-PEO blend, prepared in a 15 M acetic acid, was electrospun into nanofibers (∼ 78 nm diameter) with bead free morphology. While investigating physico-chemical parameters of blend solutions, effect of yield stress on chitosan based nanofiber fabrication was clearly evidenced. Architectural stability of nanofiber mat in aqueous medium was achieved by ionotropic cross-linking of chitosan by tripolyphosphate (TPP) ions. The TPP cross-linked nanofiber mat showed swelling up to ∼ 300% in 1 h and ∼ 40% degradation during 30 day study period. 3T3 fibroblast cells showed good attachment, proliferation and viability on TPP treated chitosan based nanofiber mats. The results indicate non-toxic nature of TPP cross-linked chitosan based nanofibers and their potential to be explored as a tissue engineering matrix. - Highlights: ► Chitosan based nanofiber fabrication through electrospinning. ► Roles of solution viscosity and yield stress on spinnability of chitosan evidenced. ► Tripolyphosphate (TPP) cross-linking rendered structural stability to nanofibers. ► TPP cross-linking also improved cellular response on chitosan based nanofibers. ► Thus, chitosan based nanofibers are suitable for tissue engineering application.

  8. Development and Characterization of Novel Films Based on Sulfonamide-Chitosan Derivatives for Potential Wound Dressing.

    Science.gov (United States)

    Dragostin, Oana Maria; Samal, Sangram Keshari; Lupascu, Florentina; Pânzariu, Andreea; Dubruel, Peter; Lupascu, Dan; Tuchilus, Cristina; Vasile, Cornelia; Profire, Lenuta

    2015-01-01

    The objective of this study was to develop new films based on chitosan functionalized with sulfonamide drugs (sulfametoxydiazine, sulfadiazine, sulfadimetho-xine, sulfamethoxazol, sulfamerazine, sulfizoxazol) in order to enhance the biological effects of chitosan. The morphology and physical properties of functionalized chitosan films as well the antioxidant effects of sulfonamide-chitosan derivatives were investigated. The chitosan-derivative films showed a rough surface and hydrophilic properties, which are very important features for their use as a wound dressing. The film based on chitosan-sulfisoxazol (CS-S6) showed the highest swelling ratio (197%) and the highest biodegradation rate (63.04%) in comparison to chitosan film for which the swelling ratio was 190% and biodegradation rate was only 10%. Referring to the antioxidant effects the most active was chitosan-sulfamerazine (CS-S5) which was 8.3 times more active than chitosan related to DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging ability. This compound showed also a good ferric reducing power and improved total antioxidant capacity. PMID:26694354

  9. Bubble template fabrication of chitosan/poly(vinyl alcohol) sponges for wound dressing applications.

    Science.gov (United States)

    Chen, Changfeng; Liu, Li; Huang, Tao; Wang, Qiong; Fang, Yue'e

    2013-11-01

    The present investigation involves the synthesis of chitosan based composite sponges in view of their applications in wound dressing, antibacterial and haemostatic. A facile CO2 bubbles template freeze-drying method was developed for the fabrication of macroporous chitosan-poly(vinyl alcohol) (PVA) composite sponges with a typical porosity of 50% and pore size of 100-300 μm. Effects of the content of cross-linking agent and PVA on morphology, mechanical properties, water uptake and moisture permeability were examined. The macroporous chitosan/PVA composite sponges exhibited an enhanced water absorption capacity over those reported microporous chitosan sponges prepared using traditional free-drying methods. Improved strength and flexibility of the chitosan sponges were observed with the presence of PVA. Further, the antibacterial and haemostatic activities have been also demonstrated. The chitosan/PVA composite sponges showed higher haemostatic activity than pure chitosan sponges and solutions. Erythrocytes cells bind first to the surface of chitosan polymer in the sponges and then promote the binding with other cells in the solution. The chitosan/PVA sponges of high liquid absorbing, appropriate moisture permeability, antimicrobial property and unique haemostatic behavior can be used for wound dressing applications.

  10. Effect of chitosan on the formation of acrylamide and hydroxymethylfurfural in model, biscuit and crust systems.

    Science.gov (United States)

    Mogol, Burçe Ataç; Gökmen, Vural

    2016-08-10

    Chitosan has been popular as a natural food preservative due to its antibacterial and antifungal activities. It may be used in thermally processed foods such as bread to delay staling and improve the microbial stability during the shelf-life. However, the thermal process could lead to the formation of harmful compounds in bakery products through chemical reactions, in which chitosan could take part. Therefore, this study aims to investigate the effect of chitosan on the formation of acrylamide and hydroxymethylfurfural (HMF) in different model systems. Addition of acid to the asparagine-glucose model system decreased the initial rate of acrylamide formation to approx. 4-times. The chitosan included model system contained higher acrylamide than the asparagine-glucose-acid model but still lower than the asparagine-glucose model system. The HMF content was decreased in the presence of acid due to acid-catalyzed degradation. Additionally, HMF is a potent carbonyl source and utilized in the Maillard reaction. In biscuit samples, addition of acid or chitosan solution to the dough did not significantly affect the acrylamide formation (p > 0.05), however addition of acid increased the formed HMF. In crust samples, acrylamide formation was decreased by acid, while chitosan showed no additional decrease. No interaction was found between HMF and chitosan. The results suggest that the effect of chitosan should be carefully evaluated apart from the effect of acid, in which chitosan was solubilized. PMID:27406058

  11. Physico-chemical/biological properties of tripolyphosphate cross-linked chitosan based nanofibers

    International Nuclear Information System (INIS)

    In this study, chitosan-PEO blend, prepared in a 15 M acetic acid, was electrospun into nanofibers (∼ 78 nm diameter) with bead free morphology. While investigating physico-chemical parameters of blend solutions, effect of yield stress on chitosan based nanofiber fabrication was clearly evidenced. Architectural stability of nanofiber mat in aqueous medium was achieved by ionotropic cross-linking of chitosan by tripolyphosphate (TPP) ions. The TPP cross-linked nanofiber mat showed swelling up to ∼ 300% in 1 h and ∼ 40% degradation during 30 day study period. 3T3 fibroblast cells showed good attachment, proliferation and viability on TPP treated chitosan based nanofiber mats. The results indicate non-toxic nature of TPP cross-linked chitosan based nanofibers and their potential to be explored as a tissue engineering matrix. - Highlights: ► Chitosan based nanofiber fabrication through electrospinning. ► Roles of solution viscosity and yield stress on spinnability of chitosan evidenced. ► Tripolyphosphate (TPP) cross-linking rendered structural stability to nanofibers. ► TPP cross-linking also improved cellular response on chitosan based nanofibers. ► Thus, chitosan based nanofibers are suitable for tissue engineering application

  12. Chitosan: Gels and Interfacial Properties

    Directory of Open Access Journals (Sweden)

    Julie Nilsen-Nygaard

    2015-03-01

    Full Text Available Chitosan is a unique biopolymer in the respect that it is abundant, cationic, low-toxic, non-immunogenic and biodegradable. The relative occurrence of the two monomeric building units (N-acetyl-glucosamine and d-glucosamine is crucial to whether chitosan is predominantly an ampholyte or predominantly a polyelectrolyte at acidic pH-values. The chemical composition is not only crucial to its surface activity properties, but also to whether and why chitosan can undergo a sol–gel transition. This review gives an overview of chitosan hydrogels and their biomedical applications, e.g., in tissue engineering and drug delivery, as well as the chitosan’s surface activity and its role in emulsion formation, stabilization and destabilization. Previously unpublished original data where chitosan acts as an emulsifier and flocculant are presented and discussed, showing that highly-acetylated chitosans can act both as an emulsifier and as a flocculant.

  13. Improvement of application properties of chitosan-based food packaging films by lavender essential oil%薰衣草精油改善壳聚糖基食品包装膜的应用品质

    Institute of Scientific and Technical Information of China (English)

    张赟彬; 王景文; 李月霞; 王一非; 姜萍萍; 刘笑宇

    2014-01-01

    potential biodegradable material due to its edibility, film-forming capacity, non-toxicity, antibacterial activity, biocompatibility and biodegradability. Traditional chitosan-based composite films are made by the casting-evaporation method. However, inferior waterproof and mechanical properties limit their applications in food package industries. Many researches have been conducted to improve the CS film. Incorporating one or several substancesinto CS film have been widespreadly used. Moreover, acetic acid and chitosan-acetate can be removed from traditionally prepared CS film by alkali leaching, resulting in lower film water-solubility. Lavender essential oil (LEO) can be used as sedative, antispasmodic, antiviral and bacteriostat in industries of perfume, aromatherapy and pharmacy. LEO can also be used as a natural spice in drink, ice cream, candy, bakery and chewing gum. In order to improve the physical and mechanical properties of conventional chitosan-based food packaging films, lavender essential oil/chitosan composite films were made with CS by casting-evaporation-alkali leaching method in this study. The films microstructures were characterized by Fourier transform infrared reflectance spectroscopy (FTIR), X-ray diffraction (XRD). The impacts of LEO content on the thickness, mechanical properties, volatiles content, water contact angle, water solubility and swelling property of films were investigated. The results indicated that the partial functional group’s locations of CS matrix were occupied by the LEO ingredients with reduced vibration intensity of covalent bond of CS. Reduced free hydrogen group could form hydrophilic bonds with water, then resulted in the loss of moisture content of films. Moreover, Chitosan-acetate content increased by incorporating LEO. The thicknesses of all films ranged from (20.60±0.34) μm to (23.35±0.65) μm. There was no linear relationship between the film thickness and LEO concentration. Tensile strength (TS) and elongation at

  14. Predicting Maize Transpiration, Water Use and Productivity for Developing Improved Supplemental Irrigation Schedules in Western Uruguay to Cope with Climate Variability

    Directory of Open Access Journals (Sweden)

    Luis Giménez

    2016-07-01

    Full Text Available Various maize irrigation treatments including full and deficit irrigation were used to calibrate and validate the soil water balance and irrigation scheduling model SIMDualKc at Paysandú, western Uruguay. The model adopts the dual crop coefficient approach to partition actual evapotranspiration (ETc act into actual transpiration (Tc act and soil evaporation (Es. Low errors of estimation were obtained for simulating soil water content (Root mean square errors (RMSE ≤ 0.014 cm3·cm−3 with calibrated parameters, and RMSE ≤ 0.023 cm3·cm−3 with default parameters. The ratio Es/Tc act ranged from 26% to 33% and Es/ETc act varied from 20% to 25%, with higher values when the crop was stressed offering less soil coverage. Due to rainfall regime, runoff and deep percolation were quite large. The Stewarts phasic model was tested and used to predict maize yield from Tc act with acceptable errors, in the range of those reported in literature. Water productivity values were high, ranging 1.39 to 2.17 kg·m−3 and 1.75 to 2.55 kg·m−3 when considering total water use and crop ET, respectively. Using a 22-year climatic data series, rainfed maize was assessed with poor results for nearly 40% of the years. Differently, alternative supplemental irrigation schedules assessed for the dry and very dry years have shown good results, particularly for mild deficit irrigation. Overall, results show appropriateness for using SIMDualKc to support the irrigation practice.

  15. Isolation and identification of indigenous plant growth promoting rhizobacteria from Himalayan region of Kashmir and their effect on improving growth and nutrient contents of maize (Zea mays L.).

    Science.gov (United States)

    Zahid, Mahwish; Abbasi, M Kaleem; Hameed, Sohail; Rahim, Nasir

    2015-01-01

    Introduction and exploitation of plant growth promoting rhizobacteria (PGPR) in agro-ecosystems enhance plant-microbes interactions that may affect ecosystems sustainability, agricultural productivity, and environmental quality. The present study was conducted to isolate and identify PGPRs associated with maize (Zea mays L.) from twenty sites of Himalayan region of Hajira-Rawalakot, Azad Jammu and Kashmir (AJK), Pakistan. A total of 100 isolates were isolated from these sites, out of which eight (HJR1, HJR2, HJR3, HJR4, HJR5, MR6, HJR7, HJR8) were selected in vitro for their plant growth promoting ability (PGPA) including phosphorus solubilization, indole-3-acetic acid (IAA) production and N2 fixation. The 16S rRNA gene sequencing technique was used for molecular identity and authentication. Isolates were then further tested for their effects on growth and nutrient contents of maize (Z. mays L.) under pouch and pot conditions. The 16S rRNA gene sequencing and phylogenetic analysis identified these isolates belong to Pseudomonas and Bacillus genera. The isolates promoted plant growth by solubilizing soil P which ranged between 19.2 and 35.6 μg mL(-1). The isolates HJR1, HJR2, HJR3, and HJR5 showed positive activity in acetylene reduction assay showing their N2-fixation potential. All eight isolates showed the potential to produce IAA in the range of 0.9-5.39 μg mL(-1) and promote plant growth. Results from a subsequent pot experiment indicated PGPRs distinctly increased maize shoot and root length, shoot and root dry weight, root surface area, leaf surface area, shoot and root N and P contents. Among the eight isolates, HR3 showed a marked P-solubilizing activity, plant growth-promoting attributes, and the potential to be developed as a biofertilizers for integrated nutrient management strategies. PMID:25852667

  16. Isolation and Identification of Indigenous Plant Growth Promoting Rhizobacteria from Himalayan Region of Kashmir and their Effect on Improving Growth and Nutrient Contents of Maize (Zea Mays L.

    Directory of Open Access Journals (Sweden)

    Mahwish eZahid

    2015-03-01

    Full Text Available IIntroduction and exploitation of plant growth promoting rhizobacteria (PGPR in agro-ecosystems enhance plant-microbes interactions that may affect ecosystems sustainability, agricultural productivity and environmental quality. The present study was conducted to isolate and identify PGPRs associated with maize (Zea mays L. from twenty sites of Himalayan region of Hajira-Rawalakot, Azad Jammu and Kashmir (AJK, Pakistan. A total of one hundred isolates were isolated from these sites, out of which eight (HJR1, HJR2, HJR3, HJR4, HJR5, MR6, HJR7, HJR8 were selected in vitro for their plant growth promoting ability (PGPA including phosphorus solubilization, indole acetic acid (IAA production and N2 fixation. The 16S rRNA gene sequencing technique was used for molecular identity and authentication. Isolates were then further tested for their effects on growth and nutrient contents of maize (Zea mays L. under pouch and pot conditions. The 16S rRNA gene sequencing and phylogenetic analysis identified these isolates belong to Pseudomonas and Bacillus genera. The isolates promoted plant growth by solubilizing soil P which ranged between 19.2 and 35.6 µgmL−1. The isolates HJR1, HJR2, HJR3 and HJR5 showed positive activity in acetylene reduction assay showing their N2-fixation potential. All eight isolates showed the potential to produce IAA in the range of 0.9−5.39 µgmL−1 and promote plant growth. Results from a subsequent pot experiment indicated PGPRs distinctly increased maize shoot and root length, shoot and root dry weight, root surface area, leaf surface area, shoot and root N and P contents. Among the eight isolates, HR3 showed a marked P-solubilizing activity, plant growth-promoting attributes, and the potential to be developed as a biofertilizers for integrated nutrient management strategies

  17. Improving the osteogenesis of human bone marrow mesenchymal stem cell sheets by microRNA-21-loaded chitosan/hyaluronic acid nanoparticles via reverse transfection

    Directory of Open Access Journals (Sweden)

    Wang Z

    2016-05-01

    Full Text Available Zhongshan Wang,1 Guangsheng Wu,2,3 Mengying Wei,4 Qian Liu,1 Jian Zhou,1 Tian Qin,1 Xiaoke Feng,1 Huan Liu,1 Zhihong Feng,1 Yimin Zhao1 1State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Oral Diseases, Department of Prosthodontics, 2State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Engineering Research Center for Dental Materials and Advanced Manufacture, Department of Periodontology, School of Stomatology, The Fourth Military Medical University, Xi’an, 3Qingdao First Sanatorium, Jinan Military Region, Qingdao, Shandong Province, 4Department of Biochemistry and Molecular Biology, The Fourth Military Medical University, Xi’an, People’s Republic of China Abstract: Cell sheet engineering has emerged as a novel approach to effectively deliver seeding cells for tissue regeneration, and developing human bone marrow mesenchymal stem cell (hBMMSC sheets with high osteogenic ability is a constant requirement from clinics for faster and higher-quality bone formation. In this work, we fabricated biocompatible and safe chitosan (CS/hyaluronic acid (HA nanoparticles (NPs to deliver microRNA-21 (miR-21, which has been proved to accelerate osteogenesis in hBMMSCs; then, the CS/HA/miR-21 NPs were cross-linked onto the surfaces of culture plates with 0.2% gel solution to fabricate miR-21-functionalized culture plates for reverse transfection. hBMMSC sheets were induced continuously for 14 days using a vitamin C-rich method on the miR-21-functionalized culture plates. For the characterization of CS/HA/miR-21 NPs, the particle size, zeta potential, surface morphology, and gel retardation were sequentially investigated. Then, the biological effects of hBMMSC sheets on the miR-21-functionalized culture plates were evaluated. The assay results demonstrated that the hBMMSC sheets could be successfully induced via the novel

  18. Radiation preservation of maize

    International Nuclear Information System (INIS)

    Radiation preservation of maize was carried out. Radiation doses and sources, shielding materials, packaging materials, chemical radiation effects, biological radiation effects, were discussed. Experimental methods, samples and accessories were also presented. (SMN)

  19. Modification of mechanical and thermal property of chitosan-starch blend films

    Science.gov (United States)

    Tuhin, Mohammad O.; Rahman, Nazia; Haque, M. E.; Khan, Ruhul A.; Dafader, N. C.; Islam, Rafiqul; Nurnabi, Mohammad; Tonny, Wafa

    2012-10-01

    Chitosan-starch blend films (thickness 0.2 mm) of different composition were prepared by casting and their mechanical properties were studied. To improve the properties of chitosan-starch films, glycerol and mustard oil of different composition were used. Chitosan-starch films, incorporated with glycerol and mustard oil, were further modified with monomer 2-hydroxyethyl methacrylate (HEMA) using gamma radiation. The modified films showed improvement in both tensile strength and elongation at break than the pure chitosan-starch films. Water uptake of the films reduced significantly than the pure chitosan-starch film. Thermo gravimetric analysis (TGA) and dynamic mechanical analysis (DMA) showed that the modified films experience less thermal degradation than the pure films. Scanning electron microscopy (SEM) and FTIR were used to investigate the morphology and molecular interaction of the blend film, respectively.

  20. Diversity in global maize germplasm: Characterization and utilization

    Indian Academy of Sciences (India)

    B M Prasanna

    2012-11-01

    Maize (Zea mays L.) is not only of worldwide importance as a food, feed and as a source of diverse industrially important products, but is also a model genetic organism with immense genetic diversity. Although it was first domesticated in Mexico, maize landraces are widely found across the continents. Several studies in Mexico and other countries highlighted the genetic variability in the maize germplasm. Applications of molecular markers, particularly in the last two decades, have led to new insights into the patterns of genetic diversity in maize globally, including landraces as well as wild relatives (especially teosintes) in Latin America, helping in tracking the migration routes of maize from the centers of origin, and understanding the fate of genetic diversity during maize domestication. The genome sequencing of B73 (a highly popular US Corn Belt inbred) and Palomero (a popcorn landrace in Mexico) in the recent years are important landmarks in maize research, with significant implications to our understanding of the maize genome organization and evolution. Next-generation sequencing and high-throughput genotyping platforms promise to further revolutionize our understanding of genetic diversity and for designing strategies to utilize the genomic information for maize improvement. However, the major limiting factor to exploit the genetic diversity in crops like maize is no longer genotyping, but high-throughput and precision phenotyping. There is an urgent need to establish a global phenotyping network for comprehensive and efficient characterization of maize germplasm for an array of target traits, particularly for biotic and abiotic stress tolerance and nutritional quality. ‘Seeds of Discovery’ (SeeD), a novel initiative by CIMMYT with financial support from the Mexican Government for generating international public goods, has initiated intensive exploration of phenotypic and molecular diversity of maize germplasm conserved in the CIMMYT Gene Bank; this

  1. IMPORTANCE OF MAIZE CROPPING

    OpenAIRE

    Mohammed Dhary Yousif EL-JUBOURI

    2012-01-01

    The Corn, wheat and rice together are the main crops. It is a plant that responds well to chemical and organic fertilization and the irrigation. But compliance is sensitive to optimum sowing time and integrated control of weeds, pests and diseases (2). The maize is the most important plant product, from the point of view commercially and is used primarily as fodder. The maize is an important source of vegetable oil and has many applications in industry, the manufacture of diverse items: cosme...

  2. Adherence of paclitaxel drug in magnetite chitosan nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Escobar Zapata, Edna V.; Martinez Perez, Carlos A.; Rodriguez Gonzalez, Claudia A.; Castro Carmona, Javier S. [Instituto de Ingenieria y Tecnologia, Universidad Autonoma de Ciudad Juarez, Ave. Del Charro 610 norte, Col. Partido Romero, C.P. 32320, Cd. Juarez Chihuahua (Mexico); Quevedo Lopez, Manuel A. [Departamento de Polimeros y Materiales, Universidad de Sonora, Blvd. Luis Encinas y Rosales, Hermosillo, Sonora (Mexico); Garcia-Casillas, Perla E., E-mail: pegarcia@uacj.mx [Instituto de Ingenieria y Tecnologia, Universidad Autonoma de Ciudad Juarez, Ave. Del Charro 610 norte, Col. Partido Romero, C.P. 32320, Cd. Juarez Chihuahua (Mexico)

    2012-09-25

    Highlights: Black-Right-Pointing-Pointer Chitosan silica magnetite adsorbs antineoplastic drug. Black-Right-Pointing-Pointer Silica coating improve the drug adherence. - Abstract: Cancer treatment is a big challenge in medicine where chemotherapies and radiotherapies are aggressive and poorly effective having side effects as delirium, fatigue, insomnia, nausea and vomiting which are common problems for cancer patients. For this reason, during the last two decades, many researchers have developed several techniques to improve the current therapies; one of them is the functionalization of magnetic nanoparticles for drug delivery. In this work, magnetic nanoparticles with an average crystallite size 21.8 nm were covered in a core/shell type; magnetite/silica, magnetite/chitosan, and a double shell magnetite/silica/chitosan were developed for attaching an antineoplastic drug. The mechanism for the functionalization of the nanoparticles with a single and double shell was studied with Fourier transformed infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The adherence of an antineoplastic drug, paclitaxel, onto functionalized nanoparticles was analyzed with a UV-Visible spectroscopy at a wavelength of 253 nm. It was found that the adherence of the drug is improved up to 18% when magnetite nanoparticles are coated with a single chitosan shell, and when the nanoparticles are coated with a silica/chitosan shell the adherence increases up to 29%.

  3. The spacer arm length in cell-penetrating peptides influences chitosan/siRNA nanoparticle delivery for pulmonary inflammation treatment

    Science.gov (United States)

    Jeong, Eun Ju; Choi, Moonhwan; Lee, Jangwook; Rhim, Taiyoun; Lee, Kuen Yong

    2015-11-01

    Although chitosan and its derivatives have been frequently utilized as delivery vehicles for small interfering RNA (siRNA), it is challenging to improve the gene silencing efficiency of chitosan-based nanoparticles. In this study, we hypothesized that controlling the spacer arm length between a cell-penetrating peptide (CPP) and a nanoparticle could be critical to enhancing the cellular uptake as well as the gene silencing efficiency of conventional chitosan/siRNA nanoparticles. A peptide consisting of nine arginine units (R9) was used as a CPP, and the spacer arm length was controlled by varying the number of glycine units between the peptide (R9Gn) and the nanoparticle (n = 0, 4, and 10). Various physicochemical characteristics of R9Gn-chitosan/siRNA nanoparticles were investigated in vitro. Increasing the spacing arm length did not significantly affect the complex formation between R9Gn-chitosan and siRNA. However, R9G10-chitosan was much more effective in delivering genes both in vitro and in vivo compared with non-modified chitosan (without the peptide) and R9-chitosan (without the spacer arm). Chitosan derivatives modified with oligoarginine containing a spacer arm can be considered as potential delivery vehicles for various genes.Although chitosan and its derivatives have been frequently utilized as delivery vehicles for small interfering RNA (siRNA), it is challenging to improve the gene silencing efficiency of chitosan-based nanoparticles. In this study, we hypothesized that controlling the spacer arm length between a cell-penetrating peptide (CPP) and a nanoparticle could be critical to enhancing the cellular uptake as well as the gene silencing efficiency of conventional chitosan/siRNA nanoparticles. A peptide consisting of nine arginine units (R9) was used as a CPP, and the spacer arm length was controlled by varying the number of glycine units between the peptide (R9Gn) and the nanoparticle (n = 0, 4, and 10). Various physicochemical characteristics of

  4. Preparation and Comparison of Chitosan Nanoparticles with Different Degrees of Glutathione Thiolation

    Directory of Open Access Journals (Sweden)

    R Dinarvand

    2011-12-01

    Full Text Available Background: Chitosan has gained considerable attentions as a biocompatible carrier to improve delivery of active agents. Application of this vehicle in the form of nanoparticle could profit advantages of nanotechnology to increase efficacy of active agents. The purpose of this study was to provide detailed information about chitosan-glutathione (Cht-GSHnanoparticles which are gaining popularity because of their high mucoadhesive and extended drug release properties. Methods: Depolymerization of chitosan was carried out using sodium nitrite method.Glutathione was covalently attached to chitosan and the solubility of the resulting conjugates was evaluated. Nanoparticles were prepared by ionic gelation method and then the effect of glutathione immobilization on properties of nanoparticles was investigated. Results: Thiolation efficiency was higher in lower molecular weight chitosan polymers compared to unmodified chitosan nanoparticles. Cht-GSH conjugates of the same molecular weight but with different degrees of thiolation had the same hydrodynamic diameter (995± nm and surface charge (102± mV as unmodified chitosan, but comprised of a denser network structure and lower concentration. Cht-GSH nanoparticles also exhibited greater mucoadhesive strength which was less affected by ionic strength and pH of the environment. Conclusion:Thiolation improves the solubility of chitosan without any significant changes in size and charge of nanoparticles, but affects the nanogel structure.

  5. A New Strategy Based on Smrho Protein Loaded Chitosan Nanoparticles as a Candidate Oral Vaccine against Schistosomiasis

    OpenAIRE

    Oliveira, Carolina R.; Rezende, Cíntia M. F.; Silva, Marina R.; Ana Paula Pêgo; Olga Borges; Alfredo M. Goes

    2012-01-01

    BACKGROUND: Schistosomiasis is one of the most important neglected tropical diseases and an effective control is unlikely in the absence of improved sanitation and vaccination. A new approach of oral vaccination with alginate coated chitosan nanoparticles appears interesting because their great stability and the ease of target accessibility, besides of chitosan and alginate immunostimulatory properties. Here we propose a candidate vaccine based on the combination of chitosan-based nanoparticl...

  6. Flocculation Kinetics of Chitosan

    Institute of Scientific and Technical Information of China (English)

    陈亮; 林志艳; 陈东辉

    2003-01-01

    Under the various conditions, the experiments of flocculation of bentonite solution with chitosan were carried out. And the flocculation kinetics was studied by the changes of floc size along with time. The results show that hydraulic gradient G (s-1) plays a key role in growing up of floc size and both of molecular weight and initial turbidity of bentonite solution influence the floc size in steady state and the time needed for steady floc size.

  7. Absorption enhancing effects of chitosan oligomers on the intestinal absorption of low molecular weight heparin in rats.

    Science.gov (United States)

    Zhang, Hailong; Mi, Jie; Huo, Yayu; Huang, Xiaoyan; Xing, Jianfeng; Yamamoto, Akira; Gao, Yang

    2014-05-15

    Absorption enhancing effects of chitosan oligomers with different type and varying concentration on the intestinal absorption of low molecular weight heparin (LMWH) were examined by an in situ closed loop method in different intestinal sections of rats. Chitosan hexamer with the optimal concentration of 0.5% (w/v) showed the highest absorption enhancing ability both in the small intestine and large intestine. The membrane toxicities of chitosan oligomers were evaluated by morphological observation and determining the biological markers including amount of protein and activity of lactate dehydrogenase (LDH) released from intestinal epithelium cells. There was no obvious change both in levels of protein and LDH and morphology in the intestinal membrane between control and various chitosan oligomers groups, suggesting that chitosan oligomers did not induce any significant membrane damage to the intestinal epithelium. In addition, zeta potentials became less negative and amount of free LMWH gradually decreased when various chitosan oligomers were added to LMWH solution, revealing that electrostatic interaction between positively charged chitosan oligomers and negative LMWH was included in the absorption enhancing mechanism of chitosan oligomers. In conclusion, chitosan oligomers, especially chitosan hexamer, are safe and efficient absorption enhancers and can be used promisingly to improve oral absorption of LMWH.

  8. Chitosan Nanoparticles-Mediated Wild-Type p53 Gene Delivery for Cancer Gene Therapy: Improvement in Pharmaceutical & Biological Properties (Enhance in Loading, Release, Expression and Stability of P53 Plasmid and Induction of Apoptosis in Carcinoma Cell Line

    Directory of Open Access Journals (Sweden)

    Mehrdad Hamidi

    2008-05-01

    Full Text Available Efficient non-viral vectors for gene delivery based on chitosan polymer is dependent on a variety of factors, e.g. loading and lelease capacity, stability in biological system and complex size. This system may have low loading, release and stability capacity. Biodegradable and biocompatible nanoparticles formulated using a chitosan polymer has the potential for sustained and controlled gene delivery. Our hypothesis is that nanoparticles-mediated wild-type p53 gene delivery would result in sustained gene expression, and hence better efficacy with a therapeutic gene. In this study, we have determined the pharmaceutical and biological characterization of Chitosan nanoparticles containing wild-type p53. Nanoparticles containing plasmid were formulated using a microemulsion reverse micellar and ionic gelation techniques. In conclusion, chitosan nanoparticles- p53 complex gene delivery results in sustained and better antiproliferative activity, which could be therapeutically beneficial in cancer treatment.

  9. Thiopyrazole preactivated chitosan: combining mucoadhesion and drug delivery.

    Science.gov (United States)

    Müller, Christiane; Ma, Benjamin N; Gust, Ronald; Bernkop-Schnürch, Andreas

    2013-05-01

    The objective of this study was to develop a preactivated chitosan derivative by the introduction of thioglycolic acid followed by 3-methyl-1-phenylpyrazole-5-thiol (MPPT) coupling via disulfide bond formation. The newly synthesized conjugate was characterized in terms of water-absorbing capacity, cohesive properties, mucoadhesion and drug release kinetics. Further in vitro characterization was conducted regarding permeation enhancement of the model compound fluorescein isothiocyanate dextran (FD4) and cytotoxic effects on Caco-2 cells. Based on the attachment of the hydrophobic residue, chitosan-S-S-MPPT test discs showed increased stability of the polymer matrix as well as improved water uptake and liberation of fluorescein isothiocyanate dextran (FD4) compared to chitosan only. The mucoadhesive qualities on porcine intestinal mucosa could be improved 38-fold based on the enhanced bonding between chitosan-S-S-MPPT and mucus through the thiol/disulfide exchange reaction of polymer and mucosal cysteine-rich domains supported by MPPT as the leaving group. This novel biomaterial presents a disulfide conjugation-based delivery system that releases the antibacterial thiopyrazole when the polymer comes into contact with the intestinal mucosa. These properties, together with the safe toxicological profile, make chitosan-S-S-MPPT a valuable carrier for mucoadhesive drug delivery systems and a promising matrix for the development of antimicrobial excipients. PMID:23321304

  10. Improving the osteogenesis of human bone marrow mesenchymal stem cell sheets by microRNA-21-loaded chitosan/hyaluronic acid nanoparticles via reverse transfection.

    Science.gov (United States)

    Wang, Zhongshan; Wu, Guangsheng; Wei, Mengying; Liu, Qian; Zhou, Jian; Qin, Tian; Feng, Xiaoke; Liu, Huan; Feng, Zhihong; Zhao, Yimin

    2016-01-01

    Cell sheet engineering has emerged as a novel approach to effectively deliver seeding cells for tissue regeneration, and developing human bone marrow mesenchymal stem cell (hBMMSC) sheets with high osteogenic ability is a constant requirement from clinics for faster and higher-quality bone formation. In this work, we fabricated biocompatible and safe chitosan (CS)/hyaluronic acid (HA) nanoparticles (NPs) to deliver microRNA-21 (miR-21), which has been proved to accelerate osteogenesis in hBMMSCs; then, the CS/HA/miR-21 NPs were cross-linked onto the surfaces of culture plates with 0.2% gel solution to fabricate miR-21-functionalized culture plates for reverse transfection. hBMMSC sheets were induced continuously for 14 days using a vitamin C-rich method on the miR-21-functionalized culture plates. For the characterization of CS/HA/miR-21 NPs, the particle size, zeta potential, surface morphology, and gel retardation were sequentially investigated. Then, the biological effects of hBMMSC sheets on the miR-21-functionalized culture plates were evaluated. The assay results demonstrated that the hBMMSC sheets could be successfully induced via the novel reverse transfection approach, and miR-21 delivery significantly enhanced the in vitro osteogenic differentiation of hBMMSC sheets in terms of upregulating calcification-related gene expression and enhancing alkaline phosphatase production, collagen secretion, and mineralized nodule formation. The enhanced osteogenic activity of hBMMSC sheets might promisingly lead to more rapid and more robust bone regeneration for clinical use. PMID:27274237

  11. Conjugating influenza a (H1N1) antigen to n-trimethylaminoethylmethacrylate chitosan nanoparticles improves the immunogenicity of the antigen after nasal administration.

    Science.gov (United States)

    Liu, Qingfeng; Zheng, Xiaoyao; Zhang, Chi; Shao, Xiayan; Zhang, Xi; Zhang, Qizhi; Jiang, Xinguo

    2015-11-01

    As one of the most serious infectious respiratory diseases, influenza A (H1N1) is a great threat to human health, and it has created an urgent demand for effective vaccines. Nasal immunization can induce both systemic and mucosal immune responses against viruses, and it can serve as an ideal route for vaccination. However, the low immunogenicity of antigens on nasal mucosa is a high barrier for the development of nasal vaccines. In this study, we covalently conjugated an influenza A (H1N1) antigen to the surface of N-trimethylaminoethylmethacrylate chitosan (TMC) nanoparticles (H1N1-TMC/NP) through thioester bonds to increase the immunogenicity of the antigen after nasal administration. SDS-PAGE revealed that most of the antigen was conjugated on TMC nanoparticles, and an in vitro biological activity assay confirmed the stability of the antigen after conjugation. After three nasal immunizations, the H1N1-TMC/NP induced significantly higher levels of serum IgG and mucosal sIgA compared with free antigen. A hemagglutination inhibition assay showed that H1N1-TMC/NP induced much more protective antibodies than antigen-encapsulated nanoparticles or alum-precipitated antigen (I.M.). In the mechanistic study, H1N1-TMC/NP was shown to stimulate macrophages to produce IL-1β and IL-6 and to stimulate spleen lymphocytes to produce IL-2 and IFN-γ. These results indicated that H1N1-TMC/NP may be an effective vaccine against influenza A (H1N1) viruses for use in nasal immunization.

  12. Hexanoyl Chitosan-based Gel Electrolyte for Lithium-ion Cell

    Institute of Scientific and Technical Information of China (English)

    Tan Winie; A.K. Arof

    2005-01-01

    @@ 1Introduction Chitosan is soluble in dilute acid solutions as a result of salt formation by the amino groups with various inorganic and organic acids[1,2]. Due to the reactivity of water and other protic solvents such as methanol and acetic acid with the electrode material in the lithiumbased electrochemicaldevices[3], the insolubility of chitosan in aprotic solvents is inadequate to meet the requirements to be used as the electrolyte materials. In order to improve its solubility in aprotic solvents,acyl modification of chitosan was carried out in the present study.Hexanoyl-chitosan (Fig. 1) that exhibited solubility in THF was prepared by reacting the chitosan with hexanoyl chloride in a mixture of pyridine and THF[4].

  13. Non-woven nanofiber chitosan/peo membranes obtained by electrospinning

    Directory of Open Access Journals (Sweden)

    M. T. M. Bizarria

    2014-03-01

    Full Text Available The present work focused on the preparation and morphological characterization of chitosan-based nanofiber membranes, aiming at applications in medical and pharmacological areas. Membranes with nanofiber diameters ranging from 50 - 300 nm were prepared from polymer solutions through the electrospinning process. To stabilize the process, it was necessary to use poly(ethylene oxide (PEO, which is a biocompatible synthetic polymer. Pure chitosan solutions, as well as chitosan and PEO solution blends, were characterized by their rheological behavior, conductivity, and surface tension measurements. The electrospun fiber thermal characteristics and crystalline structures were investigated through thermogravimetric analysis (TG and differential scanning calorimetry (DSC. Scanning electron microscopy images (SEM were used for the morphological evaluations of the membranes. The addition of PEO to the chitosan solutions improved their electrical conductivity, surface tension and viscosity, greatly favoring the electrospinning process. Thus, membranes with 80% chitosan could be electrospun.

  14. The fabrication and property of hydrophilic and hydrophobic double functional bionic chitosan film.

    Science.gov (United States)

    Wang, Xiaohong; Xi, Zhen; Liu, Zhongxin; Yang, Liang; Cao, Yang

    2011-11-01

    A new kind of hydrophobic bionic chitosan film was fabricated by simulating the surface structure of lotus leaf. The titanium oxide nanotube array was used as templates. Scanning electron microscopy (SEM) images show that one side of this films have nano-scale rough surface with spherical protrusions alike the surface of lotus leaf. The diameter of the protrusions is about 100 nm, which is equal to diameter of the titanium oxide nanotube. The water contact angle of chitosan films is up to 120 degrees and it is hydrophobic. The other side of the film is flat and the contact angle is 70 degrees. That indicated that the hydrophilism of natural materials is connected with the surface structures. The double functional chitosan films, one side is hydrophilic, the other is hydrophobic, can be made by an easy method. This method is non-toxic and clean. The double functional chitosan film will improve the application of chitosan films in medicine. PMID:22413283

  15. Effects of heat treatment on chitosan nanocomposite film reinforced with nanocrystalline cellulose and tannic acid.

    Science.gov (United States)

    Rubentheren, V; Ward, Thomas A; Chee, Ching Yern; Nair, Praveena; Salami, Erfan; Fearday, Christopher

    2016-04-20

    This article presents an analysis of the influence of heat treatment on chitosan nanocomposite film. A series of samples comprising: pure chitosan film, chitosan film embedded with nanocrystalline cellulose (NCC), chitosan film crosslinked with tannic acid and chitosan film with a blend of NCC and tannic acid were heat treated using a convection oven. Fourier-transform-infrared spectroscopy (FTIR) and X-ray diffraction test (XRD) shows the changes in chemical interaction of the heat treated films. The heat treated films show significant improvements in moisture absorption. Tensile strength and Young's Modulus were increased up to 7MPa and 259MPa, respectively when the samples were subjected to heat treatment. For the NCC particles, a transmission electron microscope (TEM) was used to inspect the structural properties of cellulose particle in suspension form.

  16. Effects of AMF on soil improvement and maize growth in mining area under drought stress%干旱胁迫下AM真菌对矿区土壤改良与玉米生长的影响

    Institute of Scientific and Technical Information of China (English)

    李少朋; 毕银丽; 陈昢圳; 陈书琳; 张延旭; 孔维平; 王瑾

    2013-01-01

    stress condition,with maize and degraded soil as the host plant and matrix,effects of arbuscular mycorrhizal fungi(AMF) on the growth and nutrient absorption of maize and the degraded soil in Shendong mine area were studied.The results showed that the treatment of inoculated AMF significantly increased the biomass and the root colonization rate of maize.Leaf relative water content and leaf color readings significantly higher than the control.The content of P,N,and Ca in shoot and the content of P,K,and Ca in root portion of maize of vaccinated treatments increased significantly.After inoculation with AMF,the phosphorus nutrition for maize was particularly improved.The phosphorus content in aerial parts of corn of inoculation treatments were on average of 0.17g/kg higher than that of non inoculation treatments and in roots were on average of 0.24g/kg.Compared with the control,the content of total glomalin and easily extractable glomalin increased by 36.2% and 33% respectively.The content of organic matter in rhizosphere soil also significantly increased.It indicated that the soil inoculated AMF promoted the mineral nutrient absorption by maize and relieved the negative effect of drought on the growth of maize and raised the content of organic matter in rhizosphere soil,which having important meaning on improvement degraded soil in mining area.Using AMF reclamation is conducive to agricultural production and has important meaning for environmental restoration and ecological restoration in Shendong coal mining subsidence area.

  17. Physiological, Biochemical and Molecular Characterization of Barley (Hordeum vulgare L.) and Maize (Zea mays L.) for Improving Manganese Efficiency

    DEFF Research Database (Denmark)

    Long, Lizhi

    Manganese (Mn) deficiency is a nutritional problem, causing significant reductions in crop yields and in severe cases resulting in complete loss of crops during winter time. Different plant species and genotypes within the same species vary in their tolerance with respect to growth in soils...... and the interaction between latent Mn deficiency and light stress in maize plants. The obtained results showed that latent Mn deficiency decreased the utilization of photosynthetically active light, inhibited the ability to perform photosynthetic state transitions and the response of net photosynthetic CO2...... assimilation to sub-saturating and saturating light. The Mn deficiency was aggravated by high light intensities which intensified the loss of stability and functionality of photosynthetic apparatus. Latent Mn deficiency in combination with high light intensities caused up-regulation of the expression...

  18. Functionalization of titanium with chitosan via silanation: evaluation of biological and mechanical performances.

    Directory of Open Access Journals (Sweden)

    Pauline Renoud

    Full Text Available Complications in dentistry and orthopaedic surgery are mainly induced by peri-implant bacterial infections and current implant devices do not prevent such infections. The coating of antibacterial molecules such as chitosan on its surface would give the implant bioactive properties. The major challenge of this type of coating is the attachment of chitosan to a metal substrate. In this study, we propose to investigate the functionalization of titanium with chitosan via a silanation. Firstly, the surface chemistry and mechanical properties of such coating were evaluated. We also verified if the coated chitosan retained its biocompatibility with the peri-implant cells, as well as its antibacterial properties. FTIR and Tof-SIMS analyses confirmed the presence of chitosan on the titanium surface. This coating showed great scratch resistance and was strongly adhesive to the substrate. These mechanical properties were consistent with an implantology application. The Chitosan-coated surfaces showed strong inhibition of Actinomyces naeslundii growth; they nonetheless showed a non significant inhibition against Porphyromonas gingivalis after 32 hours in liquid media. The chitosan-coating also demonstrated good biocompatibility to NIH3T3 fibroblasts. Thus this method of covalent coating provides a biocompatible material with improved bioactive properties. These results proved that covalent coating of chitosan has significant potential in biomedical device implantation.

  19. Development of drug-loaded chitosan-vanillin nanoparticles and its cytotoxicity against HT-29 cells.

    Science.gov (United States)

    Li, Pu-Wang; Wang, Guang; Yang, Zi-Ming; Duan, Wei; Peng, Zheng; Kong, Ling-Xue; Wang, Qing-Huang

    2016-01-01

    Chitosan as a natural polysaccharide derived from chitin of arthropods like shrimp and crab, attracts much interest due to its inherent properties, especially for application in biomedical materials. Presently, biodegradable and biocompatible chitosan nanoparticles are attractive for drug delivery. However, some physicochemical characteristics of chitosan nanoparticles still need to be further improved in practice. In this work, chitosan nanoparticles were produced by crosslinking chitosan with 3-methoxy-4-hydroxybenzaldehyde (vanillin) through a Schiff reaction. Chitosan nanoparticles were 200-250 nm in diameter with smooth surface and were negatively charged with a zeta potential of - 17.4 mV in neutral solution. Efficient drug loading and drug encapsulation were achieved using 5-fluorouracil as a model of hydrophilic drug. Drug release from the nanoparticles was constant and controllable. The in vitro cytotoxicity against HT-29 cells and cellular uptake of the chitosan nanoparticles were evaluated by methyl thiazolyl tetrazolium method, confocal laser scanning microscope and flow cytometer, respectively. The results indicate that the chitosan nanoparticles crosslinked with vanillin are a promising vehicle for the delivery of anticancer drugs.

  20. Chitosan-aprotinin coated liposomes for oral peptide delivery: Development, characterisation and in vivo evaluation.

    Science.gov (United States)

    Werle, Martin; Takeuchi, Hirofumi

    2009-03-31

    In order to improve the systemic uptake of therapeutic peptides/proteins after oral administration, the polymer-protease inhibitor conjugate chitosan-aprotinin was synthesised and polyelectrolyte complexes between negatively charged multilamellar vesicles (MLV) and positively charged chitosan-aprotinin conjugate were prepared. It could be demonstrated that chitosan-aprotinin was capable of significantly inhibiting Trypsin in vitro in concentrations of 0.05% and 0.1%, whereas no inhibition was observed in the presence of 0.1% chitosan. The size range of the prepared MLV was between 3 and 4.5microm and the initially negative zeta potential (ca. -90mV) of the core liposomes switched to a positive value after polymer coating (ca. +40mV). Confocal laser microscopy studies showed comparable mucoadhesive properties of chitosan-aprotinin coated MLV and chitosan coated MLV. In comparison to calcitonin in solution, the area above the blood calcium concentration-time curve (AAC) after oral administration of calcitonin loaded chitosan coated MLV to rats increased around 11-fold, and around 15-fold in the case of calcitonin loaded chitosan-aprotinin coated MLV. Data gained in the current study are believed to contribute to the development of novel polymer-protease inhibitor based delivery systems.

  1. Functionalization of titanium with chitosan via silanation: evaluation of biological and mechanical performances.

    Science.gov (United States)

    Renoud, Pauline; Toury, Bérangère; Benayoun, Stéphane; Attik, Ghania; Grosgogeat, Brigitte

    2012-01-01

    Complications in dentistry and orthopaedic surgery are mainly induced by peri-implant bacterial infections and current implant devices do not prevent such infections. The coating of antibacterial molecules such as chitosan on its surface would give the implant bioactive properties. The major challenge of this type of coating is the attachment of chitosan to a metal substrate. In this study, we propose to investigate the functionalization of titanium with chitosan via a silanation. Firstly, the surface chemistry and mechanical properties of such coating were evaluated. We also verified if the coated chitosan retained its biocompatibility with the peri-implant cells, as well as its antibacterial properties. FTIR and Tof-SIMS analyses confirmed the presence of chitosan on the titanium surface. This coating showed great scratch resistance and was strongly adhesive to the substrate. These mechanical properties were consistent with an implantology application. The Chitosan-coated surfaces showed strong inhibition of Actinomyces naeslundii growth; they nonetheless showed a non significant inhibition against Porphyromonas gingivalis after 32 hours in liquid media. The chitosan-coating also demonstrated good biocompatibility to NIH3T3 fibroblasts. Thus this method of covalent coating provides a biocompatible material with improved bioactive properties. These results proved that covalent coating of chitosan has significant potential in biomedical device implantation. PMID:22859940

  2. Dietary chitosan nanoparticles protect crayfish Procambarus clarkii against white spot syndrome virus (WSSV) infection.

    Science.gov (United States)

    Sun, Baozhen; Quan, Haizhi; Zhu, Fei

    2016-07-01

    Chitosan nanoparticles have exhibited potential antibacterial activity or anticancer activity as their unique character. In this study, we investigated the effect of chitosan nanoparticles protect crayfish Procambarus clarkii against WSSV. Chitosan (from crab shell) nanoparticles were prepared by ultrafine milling. The physicochemical properties of the nanoparticles were determined by particle size measure, zeta potential analysis and scanning electron microscope observation. The total hemocyte count (THC), phenoloxidase (PO) and superoxide dismutase (SOD) activity were measured at days 1, 4, 9 and 12, and the survival rate was also recorded after WSSV challenge. The results showed that chitosan nanoparticles could enhance the survival rate of WSSV-challenged crayfish. And crayfish fed diets supplemented with 10 mg/g chitosan nanoparticles (65% mortality) showed a significantly higher survival rate when compared to the control group (100% mortality). The analysis of immunological parameters revealed that 10 mg/g chitosan nanoparticles showed significantly higher level of prophenoloxidase (proPO), superoxide dismutase (SOD) and total hemocyte count (THC) when compared to the control group. It was found that chitosan nanoparticles could inhibit WSSV replication in crayfish. Our results demonstrated that dietary chitosan nanoparticles effectively improve innate immunity and survival of P. clarkii challenged with WSSV.

  3. Effect of radiation-degraded chitosan on growth promotion of flower plant in tissue culture

    Energy Technology Data Exchange (ETDEWEB)

    Luan, Le Quang; Ha, Vo Thi Thu; Hai, Le; Hien, Nguyen Quoc [Vietnam Atomic Energy Commission, Nuclear Research Institute, Dalat (Viet Nam); Nagasawa, Naotsugu; Yoshii, Fumio; Kume, Tamikazu [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    2002-03-01

    Radiation is a useful tool for degradation of polysaccharides, such as starch, carrageenan, alginate and chitin/chitosan. The viscosity molecular weight (Mw) of chitosan with 80% degree of deacetylation was reduced to 1.5 x 10{sup 5} by irradiation of 50kGy in solid phase. The solution of 10% of chitosan with Mw ca. 15 x 10{sup 5} was then irradiated at doses ranging 10-250kGy for further degradation and the products were supplemented into cultural media for testing of plant growth promotion effect. The results indicated that irradiated chitosan showed a strong growth-promotion effect on the increase of the length of shoot, the length of root and fresh biomass for flower plants namely Limonium latifolium, Eustoma grandiflorum and Chrysanthemum morifolium in tissue culture. The growth-promotion effect was obtained by the treatments with 50ppm of chitosan irradiated at the doses of 75-100kGy in 10% solution. The suitable concentrations of chitosan irradiated at 100kGy are ca. 100ppm for C. morifolium, 30ppm for E. grandiflorum and 40ppm for L. latifolium. In addition, our study also indicated that the survival ratio of transferred flower plantlets treated with irradiated chitosan was improved after acclimatizing for 30 days in the greenhouse. Accordingly, it is concluded that degraded chitosan obtained by radiation degradation technique is effective as a plant growth promoter as well as irradiated alginate. (author)

  4. Chitosan and alginate types of bio-membrane in fuel cell application: An overview

    Science.gov (United States)

    Shaari, N.; Kamarudin, S. K.

    2015-09-01

    The major problems of polymer electrolyte membrane fuel cell technology that need to be highlighted are fuel crossovers (e.g., methanol or hydrogen leaking across fuel cell membranes), CO poisoning, low durability, and high cost. Chitosan and alginate-based biopolymer membranes have recently been used to solve these problems with promising results. Current research in biopolymer membrane materials and systems has focused on the following: 1) the development of novel and efficient biopolymer materials; and 2) increasing the processing capacity of membrane operations. Consequently, chitosan and alginate-based biopolymers seek to enhance fuel cell performance by improving proton conductivity, membrane durability, and reducing fuel crossover and electro-osmotic drag. There are four groups of chitosan-based membranes (categorized according to their reaction and preparation): self-cross-linked and salt-complexed chitosans, chitosan-based polymer blends, chitosan/inorganic filler composites, and chitosan/polymer composites. There are only three alginate-based membranes that have been synthesized for fuel cell application. This work aims to review the state-of-the-art in the growth of chitosan and alginate-based biopolymer membranes for fuel cell applications.

  5. Development of drug-loaded chitosan-vanillin nanoparticles and its cytotoxicity against HT-29 cells.

    Science.gov (United States)

    Li, Pu-Wang; Wang, Guang; Yang, Zi-Ming; Duan, Wei; Peng, Zheng; Kong, Ling-Xue; Wang, Qing-Huang

    2016-01-01

    Chitosan as a natural polysaccharide derived from chitin of arthropods like shrimp and crab, attracts much interest due to its inherent properties, especially for application in biomedical materials. Presently, biodegradable and biocompatible chitosan nanoparticles are attractive for drug delivery. However, some physicochemical characteristics of chitosan nanoparticles still need to be further improved in practice. In this work, chitosan nanoparticles were produced by crosslinking chitosan with 3-methoxy-4-hydroxybenzaldehyde (vanillin) through a Schiff reaction. Chitosan nanoparticles were 200-250 nm in diameter with smooth surface and were negatively charged with a zeta potential of - 17.4 mV in neutral solution. Efficient drug loading and drug encapsulation were achieved using 5-fluorouracil as a model of hydrophilic drug. Drug release from the nanoparticles was constant and controllable. The in vitro cytotoxicity against HT-29 cells and cellular uptake of the chitosan nanoparticles were evaluated by methyl thiazolyl tetrazolium method, confocal laser scanning microscope and flow cytometer, respectively. The results indicate that the chitosan nanoparticles crosslinked with vanillin are a promising vehicle for the delivery of anticancer drugs. PMID:24712731

  6. Radiation-induced and sonochemical degradation of chitosan as a way to increase its fat-binding capacity

    Science.gov (United States)

    Czechowska-Biskup, R.; Rokita, B.; Ulanski, P.; Rosiak, J. M.

    2005-07-01

    Three physical methods of chitosan degradation: irradiation in dry state, irradiation in aqueous solution and sonication in aqueous solution were tested and compared in the terms of yields and side effects. The influence of average molecular weight of chitosan in its fat-binding ability in vitro has been studied by using a biopharmaceutical model of digestive tract. It was found that reduction in molecular weight leads to a significant increase in the amount of fat bound by 1 g of chitosan. Thus, radiation- or sonochemical treatment may be useful in improving fat-binding properties of chitosan as an active component of dietary food additives.

  7. Potassium leakage and maize seed physiological potential

    OpenAIRE

    Miguel Mariane Victorio de Carvalho; Marcos Filho Julio

    2002-01-01

    Seed production usually requires fast decisions to improve the efficacy of seed handling during harvesting, processing and storage. Seed technologists have focused on the development or improvement of procedures which allow rapid and consistent identification of higher quality seed lots. This research verified the effectiveness of the potassium leachate test on the evaluation of the physiological potential of maize seeds in comparison to recommended seed vigor tests. Five seed lots of the hyb...

  8. Chitosan grafted monomethyl fumaric acid as a potential food preservative.

    Science.gov (United States)

    Khan, Imran; Ullah, Shafi; Oh, Deog-Hwan

    2016-11-01

    The present study aims at in vitro antibacterial and antioxidant activity evaluation of chitosan modified with monomethyl fumaric acid (MFA) using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) as mediator. Three different kinds of chitosan derivatives Ch-Ds-1,Ch-Ds-2 and Ch-Ds-3 were synthesized by feeding different concentration of MFA. The chemical structures of resulting materials were characterized by (1)H NMR, (13)C NMR, HR-XRD, FT-IR and TNBS assay. The results showed that Ch-Ds-1, Ch-Ds-2 and Ch-Ds-3 were successfully synthesized. The % amino groups of chitosan modified by MFA were evaluated by TNBS assay and ranging from 1.82±0.05% to 7.88±0.04%. All the chitosan derivatives are readily soluble in water and swelled by dimethyl sulfoxide (DMSO), toluene and dimethyl formamide (DMF). The antioxidant activity for all the chitosan derivatives have been significantly improved (Pfood preservative and packaging material for long time food safety and security.

  9. Chitosan grafted monomethyl fumaric acid as a potential food preservative.

    Science.gov (United States)

    Khan, Imran; Ullah, Shafi; Oh, Deog-Hwan

    2016-11-01

    The present study aims at in vitro antibacterial and antioxidant activity evaluation of chitosan modified with monomethyl fumaric acid (MFA) using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) as mediator. Three different kinds of chitosan derivatives Ch-Ds-1,Ch-Ds-2 and Ch-Ds-3 were synthesized by feeding different concentration of MFA. The chemical structures of resulting materials were characterized by (1)H NMR, (13)C NMR, HR-XRD, FT-IR and TNBS assay. The results showed that Ch-Ds-1, Ch-Ds-2 and Ch-Ds-3 were successfully synthesized. The % amino groups of chitosan modified by MFA were evaluated by TNBS assay and ranging from 1.82±0.05% to 7.88±0.04%. All the chitosan derivatives are readily soluble in water and swelled by dimethyl sulfoxide (DMSO), toluene and dimethyl formamide (DMF). The antioxidant activity for all the chitosan derivatives have been significantly improved (Pfood preservative and packaging material for long time food safety and security. PMID:27516253

  10. Covalently Bonded Chitosan on Graphene Oxide via Redox Reaction

    Directory of Open Access Journals (Sweden)

    Víctor M. Castaño

    2013-03-01

    Full Text Available Carbon nanostructures have played an important role in creating a new field of materials based on carbon. Chemical modification of carbon nanostructures through grafting has been a successful step to improve dispersion and compatibility in solvents, with biomolecules and polymers to form nanocomposites. In this sense carbohydrates such as chitosan are extremely valuable because their functional groups play an important role in diversifying the applications of carbon nanomaterials. This paper reports the covalent attachment of chitosan onto graphene oxide, taking advantage of this carbohydrate at the nanometric level. Grafting is an innovative route to modify properties of graphene, a two-dimensional nanometric arrangement, which is one of the most novel and promising nanostructures. Chitosan grafting was achieved by redox reaction using different temperature conditions that impact on the morphology and features of graphene oxide sheets. Transmission Electron Microscopy, Fourier Transform Infrared, Raman and Energy Dispersive spectroscopies were used to study the surface of chitosan-grafted-graphene oxide. Results show a successful modification indicated by the functional groups found in the grafted material. Dispersions of chitosan-grafted-graphene oxide samples in water and hexane revealed different behavior due to the chemical groups attached to the graphene oxide sheet.

  11. Transcriptional responses of maize seedling root to phosphorus starvation.

    Science.gov (United States)

    Lin, Hai-Jian; Gao, Jian; Zhang, Zhi-Ming; Shen, Ya-Ou; Lan, Hai; Liu, Li; Xiang, Kui; Zhao, Maojun; Zhou, Shufeng; Zhang, Yong-Zhong; Gao, Shi-Bin; Pan, Guang-Tang

    2013-09-01

    Maize (Zea mays) is the most widely cultivated crop around the world, however, it is commonly affected by phosphate (Pi) deficiency and the underlying molecular basis of responses mechanism is still unknown. In this study, the transcriptional response of maize roots to Pi starvation at 3 days after the onset of Pi deprivation was assessed. The investigation revealed a total of 283 Pi-responsive genes, of which 199 and 84 genes were found to be either up- or down-regulated respectively, by 2-fold or more. Pi-responsive genes were found to be involved in sugar and nitrogen metabolic pathways, ion transport, signal transduction, transcriptional regulation, and other processes related to growth and development. In addition, the expression patterns of maize inorganic phosphorus transporters, acid phosphatase, phytase, 2-deoxymugineic acid synthase1, POD and MYB transcription factor were validated in 178 roots response to low phosphorus stress. of which, two genes encoding phytase and acid phosphatase were significantly induced by Pi deficiency and may play a pivotal role in the process of absorption and re-utilization of Pi in Maize. These results not only enhance our knowledge about molecular processes associated with Pi deficiency, but also facilitate the identification of key molecular determinants for improving Pi use in maize. Moreover, this work sets a framework to produce Pi-specific maize microarrays to study the changes in global gene expression between Pi-efficient and Pi-inefficient maize genotypes. PMID:23670044

  12. Novel atmospheric plasma enhanced chitosan nanofiber/gauze composite wound dressings

    Science.gov (United States)

    Electrospun chitosan nanofibers were deposited onto atmospheric plasma treated cotton gauze to create a novel composite bandage with higher adhesion, better handling properties, enhanced bioactivity, and moisture management. Plasma treatment of the gauze substrate was performed to improve the durabi...

  13. Genetic Architecture of Domestication-Related Traits in Maize.

    Science.gov (United States)

    Xue, Shang; Bradbury, Peter J; Casstevens, Terry; Holland, James B

    2016-09-01

    Strong directional selection occurred during the domestication of maize from its wild ancestor teosinte, reducing its genetic diversity, particularly at genes controlling domestication-related traits. Nevertheless, variability for some domestication-related traits is maintained in maize. The genetic basis of this could be sequence variation at the same key genes controlling maize-teosinte differentiation (due to lack of fixation or arising as new mutations after domestication), distinct loci with large effects, or polygenic background variation. Previous studies permit annotation of maize genome regions associated with the major differences between maize and teosinte or that exhibit population genetic signals of selection during either domestication or postdomestication improvement. Genome-wide association studies and genetic variance partitioning analyses were performed in two diverse maize inbred line panels to compare the phenotypic effects and variances of sequence polymorphisms in regions involved in domestication and improvement to the rest of the genome. Additive polygenic models explained most of the genotypic variation for domestication-related traits; no large-effect loci were detected for any trait. Most trait variance was associated with background genomic regions lacking previous evidence for involvement in domestication. Improvement sweep regions were associated with more trait variation than expected based on the proportion of the genome they represent. Selection during domestication eliminated large-effect genetic variants that would revert maize toward a teosinte type. Small-effect polygenic variants (enriched in the improvement sweep regions of the genome) are responsible for most of the standing variation for domestication-related traits in maize.

  14. Template synthesis and adsorption properties of chitosan salicylal Schiff bases

    Institute of Scientific and Technical Information of China (English)

    曹佐英; 魏琦峰; 张启修

    2004-01-01

    To improve the adsorption properties of chemically modified chitosan, the chelating resin of salicylal chitosan Schiff bases was prepared by the template cross-linking method using Cu(Ⅱ) as template ion and ethylene glycol bisglycidyl ether as cross-linking agent in microwave, and was characterized by IR. The adsorption capacity and selectivity coefficient of the chemically modified chitosan for Cu(Ⅱ), Fe(Ⅲ) and Zn(Ⅱ) were investigated, respectively. The results show that the adsorption capacity of the resin 2.73 mmol/g for Cu(Ⅱ) is bigger than that for other two metal ions, 0.22 mmol/g for Fe(Ⅲ), and 0.42 mmol/g for Zn(Ⅱ), and the selectivity coefficients are as follows: KCu(Ⅱ)/Fe(Ⅲ)=12.4, KCu(Ⅱ)/Zn(Ⅱ)=6.5.

  15. Adsorption of hexavalent chromium by graphite–chitosan binary composite

    Indian Academy of Sciences (India)

    RAJENDRA S DONGRE

    2016-06-01

    Graphite chitosan binary (GCB) composite was prepared for hexavalent chromium adsorption from studied water. GCB was characterized by TGA, FTIR, SEM and X-ray diffraction techniques.Wide porous sorptive surface of 3.89 m$^2$ g$^{−1}$ and absorptive functionalities of GCB was due to 20% (w/w) graphite support on chitosan evidenced from FTIR and SEM that impart maximum adsorption at pH 4, agitation with 200 rpm for 180 min. Adsorption studies revealed intraparticle diffusion models and best-fitted kinetics was pseudo 2nd order one. A wellfitted Langmuir isotherm model suggested monolayer adsorption with an adsorption capacity ($q_m$) of 105.6 mg g$^{−1}$ and $R^2 = 0.945$. Sorption mechanisms based on metal ionic interactions, intrusion/diffusion and chemisorptions onto composite. This graphite chitosan binary composite improve sorbent capacity for Cr(VI).

  16. Preparation and Characterization of Acylated Chitosan

    Institute of Scientific and Technical Information of China (English)

    LI Ming-chun; LIU Chao; XIN Mei-hua; ZHAO Huang; WANG Min; FENG Zhen; SUN Xiao-li

    2005-01-01

    Fully acylated chitosan and N, N-diacyl chitosan were prepared. The products were characterized by elemental analysis, FTIR and 1H NMR. The experimental results indicate that the average degree of acylation depends on the volume ratio of pyridine to chloroform in the reaction medium, the chain length of the acylation agent used, and the molecular weight of chitosan raw materials. The XRD measurements were carried out for pure chitosan, fully acylated chitosan and N, N-diacyl chitosan to verify the crystallinity change caused by the acylation.

  17. From many, one: genetic control of prolificacy during maize domestication.

    Directory of Open Access Journals (Sweden)

    David M Wills

    2013-06-01

    Full Text Available A reduction in number and an increase in size of inflorescences is a common aspect of plant domestication. When maize was domesticated from teosinte, the number and arrangement of ears changed dramatically. Teosinte has long lateral branches that bear multiple small ears at their nodes and tassels at their tips. Maize has much shorter lateral branches that are tipped by a single large ear with no additional ears at the branch nodes. To investigate the genetic basis of this difference in prolificacy (the number of ears on a plant, we performed a genome-wide QTL scan. A large effect QTL for prolificacy (prol1.1 was detected on the short arm of chromosome 1 in a location that has previously been shown to influence multiple domestication traits. We fine-mapped prol1.1 to a 2.7 kb "causative region" upstream of the grassy tillers1 (gt1 gene, which encodes a homeodomain leucine zipper transcription factor. Tissue in situ hybridizations reveal that the maize allele of prol1.1 is associated with up-regulation of gt1 expression in the nodal plexus. Given that maize does not initiate secondary ear buds, the expression of gt1 in the nodal plexus in maize may suppress their initiation. Population genetic analyses indicate positive selection on the maize allele of prol1.1, causing a partial sweep that fixed the maize allele throughout most of domesticated maize. This work shows how a subtle cis-regulatory change in tissue specific gene expression altered plant architecture in a way that improved the harvestability of maize.

  18. QTL Mapping of Low-Temperature Germination Ability in the Maize IBM Syn4 RIL Population

    OpenAIRE

    Hu, Shuaidong; Lübberstedt, Thomas; Zhao, Guangwu; Lee, Michael

    2016-01-01

    Low temperature is the primary factor to affect maize sowing in early spring. It is, therefore, vital for maize breeding programs to improve tolerance to low temperatures at seed germination stage. However, little is known about maize QTL involved in low-temperature germination ability. 243 lines of the intermated B73×Mo17 (IBM) Syn4 recombinant inbred line (RIL) population was used for QTL analysis of low-temperature germination ability. There were significant differences in germination-rela...

  19. MicroRNA Transcriptomic Analysis of Heterosis during Maize Seed Germination

    OpenAIRE

    Ding, Dong; Wang, Yinju; Han, Mingshui; Fu, Zhiyuan; Li, Weihua; Liu, Zonghua; Hu, Yanmin; Tang, Jihua

    2012-01-01

    Heterosis has been utilized widely in the breeding of maize and other crops, and plays an important role in increasing yield, improving quality and enhancing stresses resistance, but the molecular mechanism responsible for heterosis is far from clear. To illustrate whether miRNA-dependent gene regulation is responsible for heterosis during maize germination, a deep-sequencing technique was applied to germinating embryos of a maize hybrid, Yuyu22, which is cultivated widely in China and its pa...

  20. Chitosan, a new and environmental benign electrode binder for use with graphite anode in lithium-ion batteries

    International Nuclear Information System (INIS)

    Highlights: • Chitosan is used as a new electrode binder for graphite anode. • Electrochemical properties of the chitosan-based electrode are compared with that of PVDF-based one. • Electrochemical performances of the graphite anode are improved by using chitosan binder. • Chitosan binder facilitates the formation of a thin, homogenous and stable SEI film of the electrode. -- Abstract: Chitosan was applied as the electrode binder material for a spherical graphite anode in lithium-ion batteries. Compared to using poly (vinylidene fluoride) (PVDF) binder, the graphite anode using chitosan exhibited enhanced electrochemical performances in terms of the first Columbic efficiency, rate capability and cycling behavior. With similar specific capacity, the first Columbic efficiency of the chitosan-based anode is 95.4% compared to 89.3% of the PVDF-based anode. After 200 charge–discharge cycles at 0.5C, the capacity retention of the chitosan-based electrode showed to be significantly higher than that of the PVDF-based electrode. Electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM) measurements were carried out to investigate the formation and evolution of the solid electrolyte interphase (SEI) formed on the graphite electrodes. The results show that a thin, homogenous and stable SEI layer is formed on the graphite electrode surface with chitosan binder compared with that using the conventional PVDF binder

  1. Chitosan as a Modifying Component of Artificial Scaffold for Human Skin Tissue Engineering.

    Science.gov (United States)

    Romanova, O A; Grigor'ev, T E; Goncharov, M E; Rudyak, S G; Solov'yova, E V; Krasheninnikov, S T; Saprykin, V P; Sytina, E V; Chvalun, S N; Pal'tsev, M A; Panteleev, A A

    2015-08-01

    We compared the structure and mechanical properties of scaffolds based on pure collagen, pure chitosan, and a mixture of these polymers. The role of the composition and structure of scaffolds in the maintenance of cell functions (proliferation, differentiation, and migration) was demonstrated in two experimental models: homogeneous tissue analogues (scaffold populated by fibroblasts) and complex skin equivalents (fibroblasts and keratinocytes). In contrast to collagen scaffolds, pure chitosan inhibited the growth of fibroblasts that did not form contacts with chitosan fibers, but formed specific cellular conglomerates, spheroids, and lose their ability to synthesize natural extracellular matrix. However, the use of chitosan as an additive stimulated proliferative activity of fibroblasts on collagen, which can be associated with improvement of mechanical properties of the collagen scaffolds. The effectiveness of chitosan as an additional cross-linking agent also manifested in its ability to improve significantly the resistance of collagen scaffolds to fibroblast contraction in comparison with glutaraldehyde treatment. Polymer scaffolds (without cells) accelerated complete healing of skin wounds in vivo irrespective of their composition healing, pure chitosan sponge being most effective. We concluded that the use of chitosan as the scaffold for skin equivalents populated with skin cells is impractical, whereas it can be an effective modifier of polymer scaffolds. PMID:26395628

  2. Transdermal delivery of propranolol hydrochloride through chitosan nanoparticles dispersed in mucoadhesive gel.

    Science.gov (United States)

    Al-Kassas, Raida; Wen, Jingyuan; Cheng, Angel En-Miao; Kim, Amy Moon-Jung; Liu, Stephanie Sze Mei; Yu, Joohee

    2016-11-20

    This study aimed at improving the systemic bioavailability of propranolol-HCl by the design of transdermal drug delivery system based on chitosan nanoparticles dispersed into gels. Chitosan nanoparticles were prepared by ionic gelation technique using tripolyphosphate (TPP) as a cross-linking agent. Characterization of the nanoparticles was focused on particle size, zeta potential, surface texture and morphology, and drug encapsulation efficiency. The prepared freeze dried chitosan nanoparticles were dispersed into gels made of poloxamer and carbopol and the rheological behaviour and the adhesiveness of the gels were investigated. The results showed that smallest propranolol loaded chitosan nanoparticles were achieved with 0.2% chitosan and 0.05% TPP. Nanoparticles were stable in suspension with a zeta potential (ZP) above ±30mV to prevent aggregation of the colloid. Zeta potential was found to increase with increasing chitosan concentration due to its cationic nature. At least 70% of entrapment efficiency and drug loading were achieved for all prepared nanoparticles. When chitosan nanoparticles dispersed into gel consisting of poloxamer and carbopol, the resultant formulation exhibited thixotropic behaviour with a prolonged drug release properties as shown by the permeation studies through pig ear skin. Our study demonstrated that the designed nanoparticles-gel transdermal delivery system has a potential to improve the systemic bioavailability and the therapeutic efficacy of propranolol-HCl. PMID:27561485

  3. Radiation synthesis of chitosan beads grafted with acrylic acid for metal ions sorption

    Energy Technology Data Exchange (ETDEWEB)

    Benamer, S., E-mail: benamers@yahoo.fr [Division of Nuclear Applications, Centre de Recherche Nucleaire d' Alger, BP-399 Alger-Gare (Algeria); Mahlous, M.; Tahtat, D.; Nacer-Khodja, A.; Arabi, M. [Division of Nuclear Applications, Centre de Recherche Nucleaire d' Alger, BP-399 Alger-Gare (Algeria); Lounici, H.; Mameri, N. [Ecole Nationale Polytechnique d' El-Harrach Alger (Algeria)

    2011-12-15

    Radiation-induced grafting of acrylic acid onto chitosan beads was performed in solution at a dose rate of 20.6 Gy/min of cobalt-60 gamma rays. The effect of absorbed dose on grafting yield was investigated. The characterization of the grafted material was performed by FTIR spectroscopy and the swelling measurements at different pHs. The grafting yield increased with the increase in dose, it reached 80% at 40 kGy irradiation dose. The removal of Pb and Cd ions from aqueous solutions was investigated with both ungrafted and grafted chitosan beads. The sorption behavior of the sorbents was examined through pH, kinetics and equilibrium measurements. Grafted chitosan beads presented higher sorption capacity for both metal ions than unmodified chitosan beads. - Highlights: > Pb and Cd ions are removed from aqueous solution by adsorption on chitosan beads. > Crosslinking process improves chemical stability of chitosan beads. > Radiation grafting of acrylic acid onto chitosan improves its metal adsorption capacity. > Increase in grafting degree enhances the adsorption capacity of the material. > Gamma radiation is a powerful tool for an accurate control of the grafting yield.

  4. Radiation synthesis of chitosan beads grafted with acrylic acid for metal ions sorption

    International Nuclear Information System (INIS)

    Radiation-induced grafting of acrylic acid onto chitosan beads was performed in solution at a dose rate of 20.6 Gy/min of cobalt-60 gamma rays. The effect of absorbed dose on grafting yield was investigated. The characterization of the grafted material was performed by FTIR spectroscopy and the swelling measurements at different pHs. The grafting yield increased with the increase in dose, it reached 80% at 40 kGy irradiation dose. The removal of Pb and Cd ions from aqueous solutions was investigated with both ungrafted and grafted chitosan beads. The sorption behavior of the sorbents was examined through pH, kinetics and equilibrium measurements. Grafted chitosan beads presented higher sorption capacity for both metal ions than unmodified chitosan beads. - Highlights: → Pb and Cd ions are removed from aqueous solution by adsorption on chitosan beads. → Crosslinking process improves chemical stability of chitosan beads. → Radiation grafting of acrylic acid onto chitosan improves its metal adsorption capacity. → Increase in grafting degree enhances the adsorption capacity of the material. → Gamma radiation is a powerful tool for an accurate control of the grafting yield.

  5. Insect Resistant Maize 5307

    OpenAIRE

    Directorate, Issued by Health Canada's Food

    2014-01-01

    Health Canada has notified Syngenta Seeds Canada Inc. that it has no objection to the sale of food derived from Insect Resistant Maize 5307. The Department conducted a comprehensive assessment of this corn event according to its Guidelines for the Safety Assessment of Novel Foods. These Guidelines are based upon internationally accepted principles for establishing the safety of foods with novel traits.

  6. Choosing a genome browser for a Model Organism Database: surveying the maize community.

    Science.gov (United States)

    Sen, Taner Z; Harper, Lisa C; Schaeffer, Mary L; Andorf, Carson M; Seigfried, Trent E; Campbell, Darwin A; Lawrence, Carolyn J

    2010-01-01

    As the B73 maize genome sequencing project neared completion, MaizeGDB began to integrate a graphical genome browser with its existing web interface and database. To ensure that maize researchers would optimally benefit from the potential addition of a genome browser to the existing MaizeGDB resource, personnel at MaizeGDB surveyed researchers' needs. Collected data indicate that existing genome browsers for maize were inadequate and suggest implementation of a browser with quick interface and intuitive tools would meet most researchers' needs. Here, we document the survey's outcomes, review functionalities of available genome browser software platforms and offer our rationale for choosing the GBrowse software suite for MaizeGDB. Because the genome as represented within the MaizeGDB Genome Browser is tied to detailed phenotypic data, molecular marker information, available stocks, etc., the MaizeGDB Genome Browser represents a novel mechanism by which the researchers can leverage maize sequence information toward crop improvement directly. Database URL: http://gbrowse.maizegdb.org/

  7. Making better maize plants for sustainable grain production in a changing climate

    Directory of Open Access Journals (Sweden)

    Fangping eGong

    2015-10-01

    Full Text Available Achieving grain supply security with limited arable land is a major challenge in the 21st century, owing to the changing climate and increasing global population. Maize plays an increasingly vital role in global grain production. As a C4 plant, maize has a high yield potential. Maize is predicted to become the number one cereal in the world by 2020. However, maize production has plateaued in many countries, and hybrid and production technologies have been fully exploited. Thus, there is an urgent need to shape maize traits and architectures for increased stress tolerance and higher yield in a changing climate. Recent achievements in genomics, proteomics and metabolomics have provided an unprecedented opportunity to make better maize. In this paper, we discuss the current challenges and potential of maize production, particularly in China. We also highlight the need for enhancing maize tolerance to drought and heat waves, summarize the elite shoot and root traits and phenotypes, and propose an ideotype for sustainable maize production in a changing climate. This will facilitate targeted maize improvement through a conventional breeding program combined with molecular techniques.

  8. Ascorbyl palmitate-loaded chitosan nanoparticles: characteristic and polyphenol oxidase inhibitory activity.

    Science.gov (United States)

    Kim, Mi Kyung; Lee, Ji-Soo; Kim, Kwang Yup; Lee, Hyeon Gyu

    2013-03-01

    The aim of this study was to produce ascorbyl palmitate (AP)-loaded nanoparticles in order to inhibit polyphenol oxidase (PPO) in bananas. AP-loaded chitosan nanoparticles were prepared using acetic acid and citric acid (denoted as CS/AA and CS/CA nanoparticles, respectively). As the initial AP concentration increases, the particle size significantly decreases, and the zeta potential, entrapment and loading efficiency significantly increases. The PPO inhibitory activity of AP was effectively improved when AP was nano-encapsulated by chitosan compared to no encapsulation. These results suggest that chitosan nano-encapsulation can be used to enhance the PPO inhibitory activity of AP. PMID:23247266

  9. Cellular compatibility of RGD-modified chitosan nanofibers with aligned or random orientation

    Energy Technology Data Exchange (ETDEWEB)

    Wang Yanyan; Lue Lanxin; Feng Zhangqi; Xiao Zhongdang; Huang Ningping, E-mail: nphuang@seu.edu.c, E-mail: zdxiao@seu.edu.c [State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096 (China)

    2010-10-01

    Aligned and randomly oriented chitosan nanofibers were prepared by electrospinning. The fibers were modified with the RGD cell-adhesive peptide through a heterobifunctional crosslinker containing a segment of poly(ethylene glycol) (PEG). PEG rendered the surface hydrophilic and provided flexible spacers, allowing the preservation of the bioactivity of further captured RGD peptides. NIH 3T3 cells were used to test the cellular compatibility of these chitosan nanofibrous scaffolds. Cell morphology and viability were investigated by SEM, fluorescent staining and cell counting. The results indicate that RGD-modified surfaces significantly improve the cellular compatibility of chitosan nanofibers and suggest a good candidate as a scaffold employed in tissue engineering.

  10. Evaluation of Osseointegration Ability of Porous Polyethylene Implant (Medpor) Treated with Chitosan

    OpenAIRE

    Kwang Kim; Byung-Hoon Kim; Seunggon Jung; Hong-Ju Park; Seung-Ho Ohk; Hee-Kyun Oh; Min-Suk Kook

    2014-01-01

    Purpose. We suggest a successful and simple Medpor treated way with chitosan and evaluate more improved osseointegration ability of it than the orignal. Materials and Methods. Medpor was punched into circular shape and dipped into the chitosan gel solution. The Medpor plates soaked with chitosan were identified by the SEM images. We evaluated the growth rate of MC3T3-E1 cell using Von Kossa staining and MTT assay as in vitro experiment. And we implanted both Medpor plates into skull of domest...

  11. Borate cross-linked graphene oxide-chitosan as robust and high gas barrier films

    Science.gov (United States)

    Yan, Ning; Capezzuto, Filomena; Lavorgna, Marino; Buonocore, Giovanna G.; Tescione, Fabiana; Xia, Hesheng; Ambrosio, Luigi

    2016-05-01

    Chitosan (CS) is one of the most promising polymers due to its biocompatibility, biodegradability, and natural abundance. However, its poor mechanical and barrier properties make it difficult to satisfy a wide range of applications. Herein, borate ions, originating from the hydrolysis of sodium tetraborate decahydrate (borax), have been used to crosslink chitosan and graphene oxide (GO) nanocomposites. Chitosan films consisting of 1.0 wt% boron and 1.0 wt% GO exhibit a significant improvement in both the toughness and oxygen barrier properties compared to pristine chitosan. In particular the tensile strength of the samples after thermal treatment increases by ~160% compared to pristine chitosan, whereas their oxygen permeability reduces by ~90%. This is ascribed to the chemical crosslinking between chitosan and GO nanoplatelets through borate ions, as well as the formation of a layered morphology with graphene nanoplatelets oriented parallel to the sample surface. The exceptional robust and high gas barrier film has promising application in the packaging industry. The borate-crosslinking chemistry represents the potential strategy for improving properties of other polymer nanocomposites.Chitosan (CS) is one of the most promising polymers due to its biocompatibility, biodegradability, and natural abundance. However, its poor mechanical and barrier properties make it difficult to satisfy a wide range of applications. Herein, borate ions, originating from the hydrolysis of sodium tetraborate decahydrate (borax), have been used to crosslink chitosan and graphene oxide (GO) nanocomposites. Chitosan films consisting of 1.0 wt% boron and 1.0 wt% GO exhibit a significant improvement in both the toughness and oxygen barrier properties compared to pristine chitosan. In particular the tensile strength of the samples after thermal treatment increases by ~160% compared to pristine chitosan, whereas their oxygen permeability reduces by ~90%. This is ascribed to the chemical

  12. Mechanical Reinforcement of Wool Fiber through Polyelectrolyte Complexation with Chitosan and Gellan Gum

    Directory of Open Access Journals (Sweden)

    Khairul Anuar Mat Amin

    2013-10-01

    Full Text Available The formation of polyelectrolyte complex (PEC wool fibers formed by dipping chitosan or gellan gum-treated wool fibers into biopolymer solutions of opposite charge is reported. Treating wool fibers with chitosan (CH and gellan gum (GG solutions containing food dyes resulted in improved mechanical characteristics compared to wool fibers. In contrast, pH modification of the solutions resulted in the opposite effect. The mechanical characteristics of PEC-treated fibers were affected by the order of addition, i.e., dipping GG-treated fibers into chitosan resulted in mechanical reinforcement, whereas the reverse-order process did not.

  13. Curcumin-Loaded Chitosan/Gelatin Composite Sponge for Wound Healing Application

    Directory of Open Access Journals (Sweden)

    Van Cuong Nguyen

    2013-01-01

    Full Text Available Three composite sponges were made with 10% of curcumin and by using polymers, namely, chitosan and gelatin with various ratios. The chemical structure and morphology were evaluated by FTIR and SEM. These sponges were evaluated for water absorption capacity, antibacterial activity, in vitro drug release, and in vivo wound healing studies by excision wound model using rabbits. The in vivo study presented a greater wound closure in wounds treated with curcumin-composite sponge than those with composite sponge without curcumin and untreated group. These obtained results showed that combination of curcumin, chitosan and gelatin could improve the wound healing activity in comparison to chitosan, and gelatin without curcumin.

  14. The Effect of Chitosan and Sodium Alginate on the Growth and Photosynthesis of Soybean

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Seeu coating can make soybean seedling grow more strongly and reinforce the resistance of soybean plant. Sodium alginate and chitosan are high-molecular compound of two different kind,have the characteristic of promoting the crop growth. Using Sodium alginate and chitosan as coating materials under different concentration can improve the growth and photosynthesis obviously and can decrease pollution because of their characteristics. The analysis show that the effects of Sodium Alginate on soybean plant are better than chitosan and the best concentration is 0.50 g @ kg-1

  15. Chitosan and lactic acid-grafted chitosan nanoparticles as carriers for prolonged drug delivery

    OpenAIRE

    Bhattarai, Narayan; Ramay, Hassna R; Chou, Shinn-Huey; Zhang, Miqin

    2006-01-01

    Nanoparticles of ~10 nm in diameter made with chitosan or lactic acid-grafted chitosan were developed for high drug loading and prolonged drug release. A drug encapsulation efficiency of 92% and a release rate of 28% from chitosan nanoparticles over a 4-week period were demonstrated with bovine serum protein. To further increase drug encapsulation, prolong drug release, and increase chitosan solubility in solution of neutral pH, chitosan was modified with lactic acid by grafting D,L-lactic ac...

  16. Modeling and optimization of degree of folate grafted on chitosan and carboxymethyl-chitosan

    OpenAIRE

    Esfandiarpour-Boroujeni, S.; Bagheri-Khoulenjani, S.; Mirzadeh, H.

    2015-01-01

    Chitosan is a cationic polysaccharide with great properties and so is considered as an attractive biopolymer. However, chitosan shows its antibacterial activity only in acidic environment and this restricts its uses. So water-soluble chitosan derivatives such as carboxymethyl chitosan could be good candidates for such biomedical applications. Modified chitosan with hydrophobic functional groups such as folate (FA) is able to make self-assembled nanoparticles in aqueous media. One of the most ...

  17. Synthesis and evaluation of PEG-O-chitosan nanoparticles for delivery of poor water soluble drugs: Ibuprofen

    International Nuclear Information System (INIS)

    Current methods for preparation of PEGylated chitosan have limitations such as harsh de protecting step and several purification cycles. In the present study, a facile new method for conjugating methoxy polyethylene glycol (mPEG) to chitosan under mild condition is introduced to improve water solubility of chitosan and control the release of poor water soluble drugs. The method consists of chitosan modification by grafting the C6 position of chitosan to mPEG which is confirmed by Fourier transformed-infrared (FT-IR) and proton nuclear magnetic resonance (1HNMR) analyses. The amine groups at the C2 position of chitosan are protected using sodium dodecylsulfate (SDS) which is removed by dialyzing the precipitation against Tris solution. The chemical structure of the prepared polymer is characterized by FTIR and 1HNMR. The synthesized polymer is then employed to prepare nanoparticles which are characterized by transmission electron microscopy (TEM), atomic force microscopy (AFM), scanning electron microscopy (SEM), and dynamic light scattering (DLS) for their size and morphology. The nanoparticles are used for encapsulation of ibuprofen followed by in vitro release investigation in gastrointestinal and simulated biological fluids. The chitosan nanoparticles are used as control. The PEGylated nanoparticles show a particle size of 80 nm with spherical morphology. The results clearly show that drug release from PEGylated chitosan nanoparticles is remarkably slower than chitosan. In addition, drug encapsulation and encapsulation efficiency in PEGylated nanoparticles are dependent on the amount of drug added to the formulation being significantly higher than chitosan nanoparticles. This study provides an efficient, novel, and facile method for preparing a nano carrier system for delivery of water insoluble drugs. - Highlights: • A facile novel method for conjugating methoxy polyethylene glycol (mPEG) to chitosan is introduced. • Fabricated PEG-grafted chitosan

  18. Synthesis and evaluation of PEG-O-chitosan nanoparticles for delivery of poor water soluble drugs: Ibuprofen

    Energy Technology Data Exchange (ETDEWEB)

    Hassani Najafabadi, Alireza [Department of Chemistry, Amirkabir University of Technology, P.O. Box 1587-4413, Tehran (Iran, Islamic Republic of); Abdouss, Majid, E-mail: phdabdouss44@aut.ac.ir [Department of Chemistry, Amirkabir University of Technology, P.O. Box 1587-4413, Tehran (Iran, Islamic Republic of); Faghihi, Shahab [Tissue Engineering and Biomaterials Division, National Institute of Genetic Engineering and Biotechnology, Tehran 14965/161 (Iran, Islamic Republic of)

    2014-08-01

    Current methods for preparation of PEGylated chitosan have limitations such as harsh de protecting step and several purification cycles. In the present study, a facile new method for conjugating methoxy polyethylene glycol (mPEG) to chitosan under mild condition is introduced to improve water solubility of chitosan and control the release of poor water soluble drugs. The method consists of chitosan modification by grafting the C6 position of chitosan to mPEG which is confirmed by Fourier transformed-infrared (FT-IR) and proton nuclear magnetic resonance ({sup 1}HNMR) analyses. The amine groups at the C2 position of chitosan are protected using sodium dodecylsulfate (SDS) which is removed by dialyzing the precipitation against Tris solution. The chemical structure of the prepared polymer is characterized by FTIR and {sup 1}HNMR. The synthesized polymer is then employed to prepare nanoparticles which are characterized by transmission electron microscopy (TEM), atomic force microscopy (AFM), scanning electron microscopy (SEM), and dynamic light scattering (DLS) for their size and morphology. The nanoparticles are used for encapsulation of ibuprofen followed by in vitro release investigation in gastrointestinal and simulated biological fluids. The chitosan nanoparticles are used as control. The PEGylated nanoparticles show a particle size of 80 nm with spherical morphology. The results clearly show that drug release from PEGylated chitosan nanoparticles is remarkably slower than chitosan. In addition, drug encapsulation and encapsulation efficiency in PEGylated nanoparticles are dependent on the amount of drug added to the formulation being significantly higher than chitosan nanoparticles. This study provides an efficient, novel, and facile method for preparing a nano carrier system for delivery of water insoluble drugs. - Highlights: • A facile novel method for conjugating methoxy polyethylene glycol (mPEG) to chitosan is introduced. • Fabricated PEG

  19. Biocompatibility of chitosan/Mimosa tenuiflora scaffolds for tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Martel-Estrada, Santos Adriana [Instituto de arquitectura diseño y arte, Universidad Autónoma de Ciudad Juárez, Ave. Del Charro #610 norte, Col. Partido Romero, C.P. 32320 Cd. Juárez, Chihuahua (Mexico); Rodríguez-Espinoza, Brenda [Instituto de Ciencias Biomédicas, Universidad Autónoma de Ciudad Juárez, Anillo envolvente del PRONAF y Estocolmo, C.P. 32320 Cd. Juárez, Chihuahua (Mexico); Santos-Rodríguez, Elí [ICTP Meso-American Centre for Theoretical Physics (ICTP-MCTP)/Universidad Autónoma de Chiapas, Ciudad Universitaria, Carretera Zapata Km. 4, Real del Bosque (Terán), C.P. 29040 Tuxtla Gutiérrez, Chiapas (Mexico); Jiménez-Vega, Florinda [Instituto de Ciencias Biomédicas, Universidad Autónoma de Ciudad Juárez, Anillo envolvente del PRONAF y Estocolmo, C.P. 32320 Cd. Juárez, Chihuahua (Mexico); García-Casillas, Perla E.; Martínez-Pérez, Carlos A. [Instituto de Ingeniería y Tecnología, Universidad Autónoma de Ciudad Juárez, Ave. Del Charro #610 norte, Col. Partido Romero, C.P. 32320 Cd. Juárez, Chihuahua (Mexico); and others

    2015-09-15

    Highlights: • The porosity of the composites allow biological processes for the cell adaptation on the scaffolds. • The composites improve the viability and proliferation of cells. • Composition of the scaffold plays an important role in the biocompatibility. • The results indicate that Mimosa Tenuiflora can induce the differentiation of osteoblast cells. - Abstract: In search of a plant that exhibits osteogenic activity, Mimosa tenuiflora (M. tenuiflora) cortex represents the opportunity to create a biomaterial that, together with the chitosan, is osteoconductive and promote better and rapid regeneration of bone tissue. Thus, the composite of chitosan/M. tenuiflora cortex fabricated will have properties of biocompatibility and allow the osteoblast proliferation. Composites were developed with different concentrations of chitosan/M. tenuiflora cortex (w/w) using thermally induced phase separation technique (TIPS). To analyze the effects of composite on osteoblasts, primary cultures, each sample was collected on days 1, 3 and 7 after seeding. The evaluation of composites consisted of viability and proliferation tests in which we observed the metabolic activity of the cells using MTT reagent and determined the DNA concentration by means of fluorescence. The expression of the marker alkaline phosphatase (ALP) using p-nitrophenyl phosphate was examined, allowing the observation to the activity of proliferation and differentiation of osteoblastic cells. Moreover, an analysis of biomineralization was performed using scanning electron microscopy (SEM), energy dispersive spectroscopy, infrared spectroscopy and X-ray diffraction. The results showed that 80/20 chitosan/M. tenuiflora cortex biocomposite has the best performance with osteoblasts compared to biomaterials 100/0 and 70/30 chitosan/M. tenuiflora composites. Finally, it was determined that the composite of chitosan/M. tenuiflora cortex presents no cytotoxicity and increases the capacity of the osteoblasts

  20. Biocompatibility of chitosan/Mimosa tenuiflora scaffolds for tissue engineering

    International Nuclear Information System (INIS)

    Highlights: • The porosity of the composites allow biological processes for the cell adaptation on the scaffolds. • The composites improve the viability and proliferation of cells. • Composition of the scaffold plays an important role in the biocompatibility. • The results indicate that Mimosa Tenuiflora can induce the differentiation of osteoblast cells. - Abstract: In search of a plant that exhibits osteogenic activity, Mimosa tenuiflora (M. tenuiflora) cortex represents the opportunity to create a biomaterial that, together with the chitosan, is osteoconductive and promote better and rapid regeneration of bone tissue. Thus, the composite of chitosan/M. tenuiflora cortex fabricated will have properties of biocompatibility and allow the osteoblast proliferation. Composites were developed with different concentrations of chitosan/M. tenuiflora cortex (w/w) using thermally induced phase separation technique (TIPS). To analyze the effects of composite on osteoblasts, primary cultures, each sample was collected on days 1, 3 and 7 after seeding. The evaluation of composites consisted of viability and proliferation tests in which we observed the metabolic activity of the cells using MTT reagent and determined the DNA concentration by means of fluorescence. The expression of the marker alkaline phosphatase (ALP) using p-nitrophenyl phosphate was examined, allowing the observation to the activity of proliferation and differentiation of osteoblastic cells. Moreover, an analysis of biomineralization was performed using scanning electron microscopy (SEM), energy dispersive spectroscopy, infrared spectroscopy and X-ray diffraction. The results showed that 80/20 chitosan/M. tenuiflora cortex biocomposite has the best performance with osteoblasts compared to biomaterials 100/0 and 70/30 chitosan/M. tenuiflora composites. Finally, it was determined that the composite of chitosan/M. tenuiflora cortex presents no cytotoxicity and increases the capacity of the osteoblasts

  1. Beta dosimetry in intraperitoneal administration of 166Ho-chitosan

    International Nuclear Information System (INIS)

    Chitosan, a natural biodegradable polymer, was labeled with 166Ho and was administered intraperitoneally in ovarian cancer patients by diffuse intraperitoneal spread. More than 30% of administered 166Ho-chitosan complex was observed to be bound to the peritoneal surface. For the peritoneal dosimetry, all radiation emitted from 166Ho either bound to the peritoneal surface or in the peritoneal fluid should be considered. The volume of ascites is measured by dividing the 166Tc-HSA injected dose by 99mTc-HSA concentration in the ascites. The fraction of 166Ho-chitosan bound to the peritoneal surface is obtained in an indirect method by subtracting the activity in the ascites of known volume from the total adminstered activity and dividing it by standard surface area. This method has been demonstrated by applying the procedure to rats and comparing the results with the actual counts of activity concentration both on the peritoneal surface ad in the intraperitoneal fluid. For rats, about 70% of 166Ho-chitosan injected was found to attach to the peritoneal surface. With 1 mCi of 166Ho-chitosan injection, the activity was 1.3 μCi/cm2 and 2.4 μCi/ml on the peritoneal surface and in the ascites, respectively. For this specific case, the peritoneal surface dose was 105 Gy from 166Ho on the peritoneal surface and 17.8 Gy from 166Ho in the ascites. Dose estimation was performed by Monte Carlo simulation using the EGS4 code. More realistic dose estimation by applying this procedure to patients can help improve the treatment planning of ovarian cancer with 166Ho-chitosan complex

  2. FERROFERRIC OXIDE/CHITOSAN SCAFFOLDS WITH THREE-DIMENSIONAL ORIENTED STRUCTURE

    Institute of Scientific and Technical Information of China (English)

    Jia-han Ke; Zheng-ke Wang; Yin-zhe Li; Qiao-ling Hu; Jie Feng

    2012-01-01

    A facile approach to construct ferroferric oxide/chitosan composite scaffolds with three-dimensional oriented structure has been explored in this research.Chitosan and ferroferric oxide are co-precipitated by using an in situ precipitation method,and then lyophilized to get the composite scaffolds.XRD indicated that Fe3O4 was generated during the gel formation process,and increasing the content of magnetic particles could destruct the crystal structure of chitosan.When the content of magnetic particles is lower than 10%,the layer-by-layer structure and wheel spoke structure are coexisting in the scaffolds.Increasing the content of magnetic particles,just layer-by-layer structure could be observed in the scaffolds.Ferroferric oxide particles were uniformly distributed in the matrix,the size of which was about 0.48 μm in diameter,2 μm in length.Porosity of magnetic chitosan composite scaffolds is about 90%.When the ratio of ferroferric oxide to chitosan is 5/100,the compressive strength of the material is 0.4367 MPa,which is much higher than that of pure chitosan scaffolds,indicating that the layer-by-layer and wheel spokes complex structure is beneficial for the improvement of the mechanical properties of chitosan scaffolds.However,increasing the content of ferroferric oxide,the compressive strength of scaffolds decreased,because of the decreasing of chitosan crystallization and aggregation of magnetic particles as stress centralized body.Another reason is that the layer-by-layer and wheel spokes complex structure makes bigger contributions for the compressive strength than the layer-by-layer structure does.Three-dimensional ferroferric oxide/chitosan scaffolds could be used as hyperthermia generator system,improving the local circulation of blood,promoting the aggradation of calcium salt and stimulating bone tissue regeneration.

  3. Synthesis of Chitosan Quaternary Ammonium Salts

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A series of N-alkyl or N-aryl chitosan quaternary ammonium salts were prepared via Schiffs base intermediates. Quaternization of N-substituted chitosan derivatives was carried out using methyl iodide to produce water-soluble cationic chitosan quaternary ammonium salt. The products were characterized by IR, 1HNMR and elemental analysis. The degree of substitution of chitosan quaternary ammonium salt was calculated by elemental analysis.

  4. Application of irradiated chitosan for fruit preservation

    Energy Technology Data Exchange (ETDEWEB)

    Lan, K.N. [Post-harvest Technology Institute, 4, Ngo Quyen-Ha Noi (Viet Nam); Lam, N.D. [Ha Noi Radiation Center, VAEC, 5T-160, Nghiado, Tuliem, Ha Noi (Viet Nam); Kume, Tamikazu [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    2000-03-01

    Preliminary test of mango (Mangifera indica) preservation by irradiated chitosan coating has been investigated. The coating by using irradiated chitosan in 1.5% solution has extended the shelf life of mango from 7 to 15 days. At the 15th day mango coated by irradiated chitosan has been keeping good color, natural ripening, without spoilage, weight loss 10%, whereas the mango without coating was spoiled completely and the coating of fruit with unirradiated chitosan inhibited the ripening. (author)

  5. Antimicrobial properties of N-carboxybutyl chitosan.

    OpenAIRE

    Muzzarelli, R; Tarsi, R; Filippini, O; Giovanetti, E; G. Biagini; Varaldo, P E

    1990-01-01

    N-Carboxybutyl chitosan, a modified chitin of crustacean origin, displayed inhibitory, bactericidal, and candidacidal activities when tested against 298 cultures of various pathogens. Examination by electron microscopy showed that microbial cells exposed to N-carboxybutyl chitosan underwent marked morphological alterations. The data are of importance in defining the suitability of N-carboxybutyl chitosan as a wound dressing.

  6. Chitosan-supported Borohydride Reducing Agent

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A new chitosan-supported borohydride reducing reagent (CBER) was prepared by treatment of KBH4 with the resin of chitosan derivative, which was first synthesized fiom the reaction of cross-linked chitosan microsphere with glycidyl trimethylammonium chloride. CBER could reduce aromatic carbonyl compound to corresponding alcohol.

  7. The molecular understanding of interfacial interactions of functionalized graphene and chitosan

    Science.gov (United States)

    Zhang, Hong-ping; Luo, Xue-gang; Lin, Xiao-yan; Lu, Xiong; Tang, Youhong

    2016-01-01

    Graphene-reinforced chitosan scaffolds have been extensively studied for several years as promising hard tissue replacements. However, the interfacial interactions between graphene and chitosan are strongly related to the solubility, processability, and mechanical properties of graphene-reinforced chitosan (G-C) composites. The functionalization of graphene is regarded as the most effective way to improve the abovementioned properties of the G-C composite. In this study, the interfacial interactions between chitosan and functionalized graphene sheets with carboxylization (COOH-), amination (NH2-), and hydroxylation (OH-) groups were systematically studied at the electronic level using the method of ab initio simulations based on quantum mechanics theory and the observations were compared with reported experimental results. The covalent linkages between COOH-modified graphene and the chitosan units were demonstrated and the combination of multi-functionalization on graphene could regulate the interfacial interactions between graphene and the chitosan. The interfacial interactions between chitosan and properly functionalized graphene are critical for the preparation of G-C-based composites for tissue engineering scaffolds and other applications.

  8. Evaluation of Osseointegration Ability of Porous Polyethylene Implant (Medpor Treated with Chitosan

    Directory of Open Access Journals (Sweden)

    Kwang Kim

    2014-01-01

    Full Text Available Purpose. We suggest a successful and simple Medpor treated way with chitosan and evaluate more improved osseointegration ability of it than the orignal. Materials and Methods. Medpor was punched into circular shape and dipped into the chitosan gel solution. The Medpor plates soaked with chitosan were identified by the SEM images. We evaluated the growth rate of MC3T3-E1 cell using Von Kossa staining and MTT assay as in vitro experiment. And we implanted both Medpor plates into skull of domestic rabbits for in vivo experiment. We evaluated the osseointegration result with an optical microscope in postoperative 3 weeks and 6 weeks histologically. Results. The in vitro MC3T3-E1 cell growth rate on Medpor soaking with chitosan was faster than the original one in both Von Kossa staining and MTT assay. In animal test, Medpor soaking with chitosan shows more pronounced new bone than original Medpor too. Conclusion. Medpor soaking with chitosan was a successful modification. It is believed that the upgraded osseointegration ability of Medpor soaking with chitosan gives many benefits to clinicians using a Medpor implant for oral and maxillofacial reconstruction surgery.

  9. Effectiveness of Postharvest Treatment with Chitosan to Control Citrus Green Mold

    Directory of Open Access Journals (Sweden)

    Mohamed El Guilli

    2016-03-01

    Full Text Available Control of green mold, caused by Penicillium digitatum, by fungicides raises several problems, such as emergence of resistant pathogens, as well as concerns about the environment and consumers’ health. As potential alternatives, the effects of chitosan on green mold disease and the quality attributes of citrus fruits were investigated. Fruits were wounded then treated with different concentrations of chitosan 24 h before their inoculation with P. digitatum. The results of in vitro experiment demonstrated that the antifungal activity against P. digitatum was improved in concert to the increase of chitosan concentration. In an in vivo study, green mold was significantly reduced by chitosan treatments. In parallel, chitinase and glucanase activities were enhanced in coated fruits. Evidence suggested that effects of chitosan coating on green mold of mandarin fruits might be related to its fungitoxic properties against the pathogen and/or the elicitation of biochemical defense responses in coated fruits. Further, quality attributes including fruit firmness, surface color, juice content, and total soluble solids, were not affected by chitosan during storage. Moreover, the loss of weight was even less pronounced in chitosan-coated fruit.

  10. THE DEVELOPMENT OF CHITOSAN NANOPARTICLES FROM HIBISCUS SABDARIFFA L CALYX EXTRACT FROM INDONESIA AND THAILAND

    Directory of Open Access Journals (Sweden)

    Nurkhasanah*, Tedjo Yuwono, Laela Hayu Nurani, Muhammad Ikhwan Rizki and Krisana Kraisintu

    2015-05-01

    Full Text Available Rosella (Hibiscus sabdariffa L calyx has been reported to have an antioxidant activity. Antocyanidin is the major compound of rosella and has low bioavailability as an ionic form. Rosella extract is an ucceptable due to high acidity. Development of chitosan nanoparticle from Hibiscus sabdariffa extract were expected to improve the bioavailability and the acidity problem. We studied the optimum pH and composition ratios of chitosan, extract and tripolyphosphate (TPP to develop chitosan-nanoparticle of rosella extract. We used rosella calyx both from Indonesia and Thailand to compare the physical characteristic the extract and nanoparticles. Rosella was extracted using 60% ethanol and water, followed by evaporation using evaporator and dried by freezedryer. The optimum formation of chitosan-nanoparticles of rosella extract were observed including pH formation and composition ratios between extract: chitosan: TPP. The physical charactersitics of nanoparticles were observed using transmission electron microscope (TEM and particle size analyzer (PSA. We found that optimum composition of extract: chitosan : TPP ratios were 2 : 1 : 0.1, with optimum formation of chitosan in acetate buffer pH 4. The characteristic of nanoparticles were spherical shapes with particles size range 60 to 300 nm, polydispersity index around 0.3 and zeta potential 39.19 to 62.26 mV. The nanoparticles has high entrapment efficiency of flavonoid active compound of 81.98 to 83.83%.

  11. Controlling Properties and Cytotoxicity of Chitosan Nanocapsules by Chemical Grafting

    Science.gov (United States)

    De Matteis, Laura; Alleva, Maria; Serrano-Sevilla, Inés; García-Embid, Sonia; Stepien, Grazyna; Moros, María; de la Fuente, Jesús M.

    2016-01-01

    The tunability of the properties of chitosan-based carriers opens new ways for the application of drugs with low water-stability or high adverse effects. In this work, the combination of a nanoemulsion with a chitosan hydrogel coating and the following poly (ethylene glycol) (PEG) grafting is proven to be a promising strategy to obtain a flexible and versatile nanocarrier with an improved stability. Thanks to chitosan amino groups, a new easy and reproducible method to obtain nanocapsule grafting with PEG has been developed in this work, allowing a very good control and tunability of the properties of nanocapsule surface. Two different PEG densities of coverage are studied and the nanocapsule systems obtained are characterized at all steps of the optimization in terms of diameter, Z potential and surface charge (amino group analysis). Results obtained are compatible with a conformation of PEG molecules laying adsorbed on nanoparticle surface after covalent linking through their amino terminal moiety. An improvement in nanocapsule stability in physiological medium is observed with the highest PEG coverage density obtained. Cytotoxicity tests also demonstrate that grafting with PEG is an effective strategy to modulate the cytotoxicity of developed nanocapsules. Such results indicate the suitability of chitosan as protective coating for future studies oriented toward drug delivery. PMID:27706041

  12. Characterization of Maize Producing Households in Southern Zambia

    Directory of Open Access Journals (Sweden)

    Thomson Kalinda

    2014-01-01

    Full Text Available Maize is an important crop in the livelihood of Zambia’s most vulnerable populations. A huge challenge facing most of Sub-Saharan Africa (SSA countries like Zambia is to increase maize productivity of smallholder farmers, which has remained very low over the past decades. Through various breeding programmes, more than 50 new maize hybrids and open-pollinated varieties have been developed and provided to the farmers through seed companies and Non-Governmental Organizations (NGOs. However, the extent to which such varieties have been adopted remains unknown. The purpose of this study was to characterize the maize producing households and to assess adoption of improved maize varieties. Data were collected from randomly selected households in the maize-producing areas of Monze and Kalomo Districts in southern Zambia. Principal Components Analysis (PCA on asset ownership was used to generate a wealth index used to rank the survey households. The results confirm that poorly endowed households, most of whom are female-headed, are far less likely to adopt improved varieties than their well-off counterparts. Important maize variety attributes sought by farmers include early maturity (85% of households, tolerance to water stress (83%, yield potential (79%, pest/disease resistance (56%, better processing quality (56% and cob/grain size (50%. A larger proportion of well endowed households planted improved varieties, compared with their poorly endowed counterparts. These findings suggest that moving the poor households and female-headed households up the wealth ladder poses a considerable challenge and calls for targeting the key factors that could potentially improve their welfare.

  13. Mechanical Reinforcement of Wool Fiber through Polyelectrolyte Complexation with Chitosan and Gellan Gum

    OpenAIRE

    Khairul Anuar Mat Amin; Marc in het Panhuis

    2013-01-01

    The formation of polyelectrolyte complex (PEC) wool fibers formed by dipping chitosan or gellan gum-treated wool fibers into biopolymer solutions of opposite charge is reported. Treating wool fibers with chitosan (CH) and gellan gum (GG) solutions containing food dyes resulted in improved mechanical characteristics compared to wool fibers. In contrast, pH modification of the solutions resulted in the opposite effect. The mechanical characteristics of PEC-treated fibers were affected by the or...

  14. Immobilization of Lipase from Candida rugosa on Chitosan Beads for Transesterification Reaction

    OpenAIRE

    M. Nasratun; H. A. Said; Noraziah, A.; A. N.A. Alla

    2009-01-01

    Problem statement: Further study is recommended to improve the immobilization technique and the immobilized lipases performance as catalysis in transesterification reaction. Approach: To investigate the ability of immobilized lipase on chitosan beads to catalyze the transesterification of cooking oil to an ester. The porous bead of chitosan was used for immobilization of lipase from Candida rugosa by physical adsorption. Parameters like reaction time and oil to methanol molar ratios were stud...

  15. LYOTROPIC LIQUID CRYSTALLINE BEHAVIOR OF FIVE CHITOSAN DERIVATIVES

    Institute of Scientific and Technical Information of China (English)

    Yan-ming Dong; Zhi-qiang Li

    1999-01-01

    Five chitosan derivatives, i.e. O-butyryl chitosan, O-benzoyl chitosan, N-phthaloyl chitosan, N-maleoyl chitosan and O-cyanoethyl chitosan, were prepared from chitosan. All of them had better solubilitythan chitosan, and demonstrated lyotropic liquid crystalline behavior in various solvents. The critical liquid crystalline behavior of three O-substituted chitosan derivatives was evidently different from two Nsubstituted analogues. Typical fingerprint textures of cholesteric phase were only observed in three Osubstituted derivatives. The critical concentration (v/v%) of three O-substituted derivatives does not depend on the acidity of acidic solvents.

  16. Maize and wheat yield improvement on small-scale farms in Uasin Gishu district: (I) The diagnosis of causes of low and declining yields (II) Proposed interventions to the identified constraint(s)

    International Nuclear Information System (INIS)

    Maize and wheat yields have been declining over the years in Uasin Gishu district. The average yields for maize and wheat from small-scale farms are 4200 and 1655 kg ha4, respectively (Hassan and Mwangi, 1991). The most popular and commonly used fertilizer for maize and wheat production in this area is di-ammonium phosphate (DAP). Acid soils caused by application of DAP has been suspected as one of the major constraints to production of these crops in the region. However, work in the same region on the influence of DAP on soil pH has indicated no effect (Ogola and Oduor, 1993). It is also suspected that poor soil fertility in general (soil fertility depletion) and degraded soils (low organic matter content soils) are constraints to maize and wheat production in the district. (author)

  17. The role of cis regulatory evolution in maize domestication.

    Science.gov (United States)

    Lemmon, Zachary H; Bukowski, Robert; Sun, Qi; Doebley, John F

    2014-11-01

    Gene expression differences between divergent lineages caused by modification of cis regulatory elements are thought to be important in evolution. We assayed genome-wide cis and trans regulatory differences between maize and its wild progenitor, teosinte, using deep RNA sequencing in F1 hybrid and parent inbred lines for three tissue types (ear, leaf and stem). Pervasive regulatory variation was observed with approximately 70% of ∼17,000 genes showing evidence of regulatory divergence between maize and teosinte. However, many fewer genes (1,079 genes) show consistent cis differences with all sampled maize and teosinte lines. For ∼70% of these 1,079 genes, the cis differences are specific to a single tissue. The number of genes with cis regulatory differences is greatest for ear tissue, which underwent a drastic transformation in form during domestication. As expected from the domestication bottleneck, maize possesses less cis regulatory variation than teosinte with this deficit greatest for genes showing maize-teosinte cis regulatory divergence, suggesting selection on cis regulatory differences during domestication. Consistent with selection on cis regulatory elements, genes with cis effects correlated strongly with genes under positive selection during maize domestication and improvement, while genes with trans regulatory effects did not. We observed a directional bias such that genes with cis differences showed higher expression of the maize allele more often than the teosinte allele, suggesting domestication favored up-regulation of gene expression. Finally, this work documents the cis and trans regulatory changes between maize and teosinte in over 17,000 genes for three tissues.

  18. The role of cis regulatory evolution in maize domestication.

    Directory of Open Access Journals (Sweden)

    Zachary H Lemmon

    2014-11-01

    Full Text Available Gene expression differences between divergent lineages caused by modification of cis regulatory elements are thought to be important in evolution. We assayed genome-wide cis and trans regulatory differences between maize and its wild progenitor, teosinte, using deep RNA sequencing in F1 hybrid and parent inbred lines for three tissue types (ear, leaf and stem. Pervasive regulatory variation was observed with approximately 70% of ∼17,000 genes showing evidence of regulatory divergence between maize and teosinte. However, many fewer genes (1,079 genes show consistent cis differences with all sampled maize and teosinte lines. For ∼70% of these 1,079 genes, the cis differences are specific to a single tissue. The number of genes with cis regulatory differences is greatest for ear tissue, which underwent a drastic transformation in form during domestication. As expected from the domestication bottleneck, maize possesses less cis regulatory variation than teosinte with this deficit greatest for genes showing maize-teosinte cis regulatory divergence, suggesting selection on cis regulatory differences during domestication. Consistent with selection on cis regulatory elements, genes with cis effects correlated strongly with genes under positive selection during maize domestication and improvement, while genes with trans regulatory effects did not. We observed a directional bias such that genes with cis differences showed higher expression of the maize allele more often than the teosinte allele, suggesting domestication favored up-regulation of gene expression. Finally, this work documents the cis and trans regulatory changes between maize and teosinte in over 17,000 genes for three tissues.

  19. The Role of cis Regulatory Evolution in Maize Domestication

    Science.gov (United States)

    Lemmon, Zachary H.; Bukowski, Robert; Sun, Qi; Doebley, John F.

    2014-01-01

    Gene expression differences between divergent lineages caused by modification of cis regulatory elements are thought to be important in evolution. We assayed genome-wide cis and trans regulatory differences between maize and its wild progenitor, teosinte, using deep RNA sequencing in F1 hybrid and parent inbred lines for three tissue types (ear, leaf and stem). Pervasive regulatory variation was observed with approximately 70% of ∼17,000 genes showing evidence of regulatory divergence between maize and teosinte. However, many fewer genes (1,079 genes) show consistent cis differences with all sampled maize and teosinte lines. For ∼70% of these 1,079 genes, the cis differences are specific to a single tissue. The number of genes with cis regulatory differences is greatest for ear tissue, which underwent a drastic transformation in form during domestication. As expected from the domestication bottleneck, maize possesses less cis regulatory variation than teosinte with this deficit greatest for genes showing maize-teosinte cis regulatory divergence, suggesting selection on cis regulatory differences during domestication. Consistent with selection on cis regulatory elements, genes with cis effects correlated strongly with genes under positive selection during maize domestication and improvement, while genes with trans regulatory effects did not. We observed a directional bias such that genes with cis differences showed higher expression of the maize allele more often than the teosinte allele, suggesting domestication favored up-regulation of gene expression. Finally, this work documents the cis and trans regulatory changes between maize and teosinte in over 17,000 genes for three tissues. PMID:25375861

  20. Toward Cost-Effective Fingerprinting Methodology to Distinguish Maize Open-Pollinated Varieties

    Science.gov (United States)

    In Africa, many smallholder farmers grow open pollinated maize varieties (OPVs), as they allow seed recycling and out-yield traditional farmer’s (unimproved) landraces. One popular OPV, ZM521 released by the International Maize and Wheat Improvement Center (CIMMYT), has been provided to farmers, o...

  1. Effect of PEGylation on the toxicity and permeability enhancement of chitosan.

    Science.gov (United States)

    Casettari, Luca; Vllasaliu, Driton; Mantovani, Giuseppe; Howdle, Steven M; Stolnik, Snow; Illum, Lisbeth

    2010-11-01

    The aim of the present work is to investigate if conditions can be devised where PEGylation of chitosan would reduce its toxicity toward the nasal mucosa while maintaining its ability to open the cellular tight junctions and, consequently, produce an enhancement of macromolecular permeability. A series of mPEG-g-chitosan copolymers with varying levels of mPEG substitution, mPEG molecular weight, and chitosan molecular weight were synthesized by grafting carboxylic acid-terminated mPEGs (Mw 1.9 and 5.0 × 10(3) g mol(-1)) to chitosans (Mw 28.9 and 82.0 × 10(3) g mol(-1)) using a NHS/EDC coupling system. The synthesized mPEG-g-chitosans were fully characterized using a number of techniques, including FT-IR, (1)H NMR, and SEC-MALLS and their physicochemical properties were analyzed by TGA and DSC. Thereafter, the conjugates were tested for their cytotoxicity and tight junction modulating property in a relevant cell model, a mucus producing Calu-3 monolayer. mPEG-g-chitosan conjugates exhibited reduced toxicity toward cells, as compared to unmodified chitosan counterparts. Furthermore, the conjugates demonstrated a dramatic effect on cell monolayer transepithelial electrical resistance (TEER) and enhancement of permeability of model macromolecules. TEER and permeability-enhancing effects, as measurable indicators of tight junction modulation, were found to be pH-dependent and were notably more pronounced than those exhibited by unmodified chitosans. This work therefore demonstrates that conditions can be contrived where PEGylation improves the toxicity profile of chitosan, while preserving its effect on epithelial tight junctions in the nose. PMID:20873757

  2. Effects of chitosan on nutrient digestibility, methane emissions, and in vitro fermentation in beef cattle.

    Science.gov (United States)

    Henry, D D; Ruiz-Moreno, M; Ciriaco, F M; Kohmann, M; Mercadante, V R G; Lamb, G C; DiLorenzo, N

    2015-07-01

    Chitosan was evaluated as a feed additive to mitigate in vivo CH4 emissions in beef cattle. Twenty-four crossbred heifers (BW = 318 ± 35 kg) were used in a randomized block design replicated in 2 periods. The design included a 2 × 3 factorial arrangement of treatments, which included diet (high concentrate [HC] or low concentrate [LC]) and 0.0, 0.5, or 1.0% of chitosan inclusion (DM basis). Diets were offered ad libitum and individual intake was recorded. An in vitro experiment to analyze chitosan’s effect on fermentation parameters and gas production kinetics was performed. A diet effect (P 0.10) by chitosan in HC substrate; however, when incubated with the LC substrate, CH4 production increased quadratically (P < 0.01) as chitosan inclusion increased. A digestibility marker × diet interaction occurred (P < 0.05) for DM, OM, CP, NDF, and ADF digestibility. Diet × chitosan interactions (P < 0.05) occurred for DM, OM, NDF, and ADF digestibility when Cr2O3 was used. When TiO2 was used, diet × chitosan interactions (P < 0.05) were observed for NDF and ADF. However, using indigestible NDF as an internal marker, DM and OM digestibility were improved (P < 0.05) by 21 and 19%, respectively, when chitosan was included in LC diets. In conclusion, feeding up to 1% of chitosan (DM basis) to heifers consuming a LC diet increased apparent total tract digestibility of nutrients. Enteric CH4 emissions were not affected by chitosan feeding, regardless of type of diet, and heifers consuming a 36% concentrate diet produced 2.6 times more methane per day than those consuming an 85% concentrate diet. PMID:26440023

  3. Physical characteristics of chitosan-silica composite of rice husk ash

    Science.gov (United States)

    Sumarni, Woro; Sri Iswari, Retno; Marwoto, Putut; Rahayu, Endah F.

    2016-02-01

    Some previous studies showed that the characteristics of chitosan membranes have a very rigid and non-porous structure so that its utilization is not maximized, particularly in the filtration process. Hence, it needs modification to improve the quality of the chitosan membranes. Adding the silica into the chitosan membranes is one of the offered solutions to overcome the problems of physical and mechanical properties of chitosan. This study aims to investigate the effect of variations in the silica composition to the physical characteristics of the chitosan-silica membranes of rice husk ash that were synthesized. The chitosan used is derived from the chitin of Vannamei shrimps’ shell with 82% degree of de-acetylation, while the silica was synthesized from rice husk ash with rendering of silica (SiO2) by 5% and the results of XRD analysis showed an amorphous phase. Membrane synthesis was performed using the phase inversion method with chitosan-silica mass ratios of rice husk ash, which were 1:0.0; 1:0.5; 1:1.0; 1:1.5 and 1:2.0. The results showed that the addition of silica increases the swelling index and the membrane permeability. The results of the analysis, FTIR spectra, obtained a new functional group after the addition of silica, they are Si-OH, Si-O-Si, and CO- NH2. The morphology test using CCD Microscope MS-804 results in the very tight chitosan membranes without the silica surface, it has no pores, smooth and homogeneous, while the chitosan-silica composite membrane of rice husk ash obviously has cracks and small cavities that seemed to spread out.

  4. Simulation of water use process by film mulched cultivated maize based on improved AquaCrop model and its verification%基于改进AquaCrop模型的覆膜栽培玉米水分利用过程模拟与验证

    Institute of Scientific and Technical Information of China (English)

    杨宁; 孙占祥; 张立桢; 郑家明; 冯良山; 李开宇; 张哲; 冯晨

    2015-01-01

    -mulched maize was among ±6%. In addition, R2, RRMSE, CE of grain and water use efficiency during 2011 to 2013 were 0.96 and 0.93, 0.042 and 0.06, 0.91 and 0.89, respectively. The developed AquaCrop model predicted maize grain yield with higher accuracy and performed better yield than water use efficiency for mulching plastic film maize, which indicated this improved model were better mechanism and application for simulated maize mulching. The present research implicated that the developed AquaCrop model can be applied to the same to semi-arid region and simulated maize potential, or prescribing yield in response to water and temperature limiting factors under climate change.

  5. 玉米外引自交系及改良系穗部性状的遗传分析%Genetic Analysis of Ear Traits of Exotic and Improved Maize Inbred Lines

    Institute of Scientific and Technical Information of China (English)

    郭琦; 李继竹; 杨伟光; 尹日成

    2013-01-01

    以7个外引玉米自交系及改良系和6个国内骨干自交系按照 NCⅡ设计组配42个杂交组合,对其8个主要穗部性状进行了遗传分析。结果表明:7923、6WC、J1782的一般配合力较高,是综合性状较好的自交系。配合力与产量相关分析结果表明:一般配合力比特殊配合力相关明显,在玉米育种实践中应重视对性状一般配合力的选择。特殊配合力和杂种优势分析结果表明:7923×8F349,7923×丹340等9个组合为高产杂交组合。遗传力分析结果表明:穗长、穗粗和穗行数的广义遗传力和狭义遗传力均较大,可早代选择;子粒长、秃尖长、出子率、百粒重的狭义遗传力相对较低,不应早代选择。%Seven exotic and improved maize inbred lines were crossed with six elite Chinese inbred lines and 42 combinations were produced according to NCⅡ design.Eight main ear traits were genetically ana-lyzed.The results showed that inbred lines 7923,6WC and J1782 had high combining ability,which were good lines;combining ability and yield correlation analysis showed that in maize breeding,GCA was more important than SCA;we selected 7 high-yield combinations through heterosis analysis,like 7923 × 8-F349;broad heritability and narrow heritability of ear length,ear diameter and ear row number were high,so they could be selected in early generation;narrow heritability of kernel length,length of bare tip,seed ratio and hundred-grain weight was low,and they are easy to be impacted by environment,so they should not be selected in early generation.

  6. Methylated 4-N,N dimethyl aminobenzyl N,O carboxymethyl chitosan as a new chitosan derivative: Synthesis, characterization, cytotoxicity and antibacterial activity.

    Science.gov (United States)

    Rahmani, Soheila; Mohammadi, Zohreh; Amini, Mohsen; Isaei, Elham; Taheritarigh, Sadegh; Rafiee Tehrani, Niyousha; Rafiee Tehrani, Morteza

    2016-09-20

    Chitosan, as a biocompatible polymer, is very attractive for biomedical applications. Continues studies are performing for improving its physicochemical features in order to make it more suitable for such approaches. In this study, methylated 4-N,N dimethyl aminobenzyl N,O carboxymethyl chitosan (MABCC) was synthesized,as a new chitosan derivative, in three steps. The investigations were carried out using FTIR, NMR, TGA and zeta potential measurement. Antibacterial and cell viability assessments were performed on four bacterial strains and two cell lines respectively. FTIR and NMR results showed that all substitution reactions were successfully carried out. Zeta potential of MABCC at various pH especially alkaline pH was greater than chitosan and it revealed increasing the solubility of the derivative. Antibacterial activity of MABCC was extremely greater than chitosan especially in Gram positive bacteria.Furthermore,it had no significant cytotoxicity against MCF-7 and Skov-3 cell lines in comparison to chitosan. These findings confirm that this new derivative can be introduced as a suitable compound for biomedical purposes.

  7. Methylated 4-N,N dimethyl aminobenzyl N,O carboxymethyl chitosan as a new chitosan derivative: Synthesis, characterization, cytotoxicity and antibacterial activity.

    Science.gov (United States)

    Rahmani, Soheila; Mohammadi, Zohreh; Amini, Mohsen; Isaei, Elham; Taheritarigh, Sadegh; Rafiee Tehrani, Niyousha; Rafiee Tehrani, Morteza

    2016-09-20

    Chitosan, as a biocompatible polymer, is very attractive for biomedical applications. Continues studies are performing for improving its physicochemical features in order to make it more suitable for such approaches. In this study, methylated 4-N,N dimethyl aminobenzyl N,O carboxymethyl chitosan (MABCC) was synthesized,as a new chitosan derivative, in three steps. The investigations were carried out using FTIR, NMR, TGA and zeta potential measurement. Antibacterial and cell viability assessments were performed on four bacterial strains and two cell lines respectively. FTIR and NMR results showed that all substitution reactions were successfully carried out. Zeta potential of MABCC at various pH especially alkaline pH was greater than chitosan and it revealed increasing the solubility of the derivative. Antibacterial activity of MABCC was extremely greater than chitosan especially in Gram positive bacteria.Furthermore,it had no significant cytotoxicity against MCF-7 and Skov-3 cell lines in comparison to chitosan. These findings confirm that this new derivative can be introduced as a suitable compound for biomedical purposes. PMID:27261738

  8. SYNTHESIS AND PROPERTIES OF SULFHYDRYL CHITOSAN

    Institute of Scientific and Technical Information of China (English)

    杨宇民; 邵健; 姚成

    2001-01-01

    A new adsorbent for heavy metal ions, sulfhydryl chitosan (S-chitosan), was produced by treatment of chitosan with sulhydryl acetic acid in the presence of sulfuric acid as a catalyst. Its structure was confrrmed by elemental analysis and FI'-IR spectra analysis. The adsorption properties of sulthydryl chitosan for Cu(Ⅱ ), Cd(Ⅱ ), Pb(Ⅱ), Cr(Ⅲ) and Ni(Ⅱ) were investigated, and the effect of pH value on adsorption, adsorption kinetics, and selective adsorption was examined. It was shown that S-chitosan has good adsorption for Pb(Ⅱ), Cu(Ⅱ) and Cd(Ⅱ) like chitosan, is also insoluble in acid solution; has good adsorption kinetic properties for heavy metal ions; and can be used in acid solution. The adsorption capacities of S-chitosan can be affected by media acidity. The adsorbed Cu(Ⅱ) Cd(Ⅱ) and Pb(Ⅱ) could be eluted by diluted chlorhydric acid.

  9. SYNTHESIS AND PROPERTIES OF SULFHYDRYL CHITOSAN

    Institute of Scientific and Technical Information of China (English)

    杨宇民; 邵健; 姚成

    2001-01-01

    A new adsorbent for heavy metal ions, sulfhydryl chitosan (S-chitosan), was produced by treatment of chitosan with sulhydryl acetic acid in the presence of sulfuric acid as a catalyst. Its structure was confirmed by elemental analysis and FT-IR spectra analysis. The adsorption properties of sulfhydryl chitosan for Cu( Ⅱ ), Cd( Ⅱ ), Pb( Ⅱ ), Cr( Ⅲ ) and Ni( Ⅱ ) were investigated, and the effect of pH value on adsorption, adsorption kinetics, and selective adsorption was examined. It was shown that S-chitosan has good adsorption for Pb( Ⅱ ), Cu( Ⅱ ) and Cd( Ⅱ ) like chitosan, is also insoluble in acid solution; has good adsorption kinetic properties for heavy metal ions; and can be used in acid solution. The adsorption capacities of S-chitosan can be affected by media acidity. The adsorbed Cu( Ⅱ ) Cd ( Ⅱ )and Pb( Ⅱ ) could be eluted by diluted chlorhydric acid.

  10. Anti-fungal activity of irradiated chitosan

    International Nuclear Information System (INIS)

    Anti-fungal activity of chitosan induced by irradiation has been investigated. Commercial chitosan samples of 8B (80% deacetylation) and l0B (99% deacetylation) were irradiated by γ-ray in dry condition. Highly deacethylated chitosan (10B) at low dose irradiation (75 kGy) was effective for inhibition of fungal growth. The sensitivities of Exobasidium vexans, Septoria chrysanthemum and Gibberella fujikuroi for the irradiated chitosan were different and the necessary concentrations of chitosan were 550, 350 and 250 μg/ml, respectively. For the plant growth, low deacethylation (chitosan 8B) and high dose (500 kGy) was effective and the growth of chrysanthemum was promoted by spraying the irradiated chitosan. (author)

  11. Influence of Water Stress on Endogenous Hormone Contents and Cell Damage of Maize Seedlings

    Institute of Scientific and Technical Information of China (English)

    Chunrong Wang; Aifang Yang; Haiying Yin; Juren Zhang

    2008-01-01

    Phytohormones play critical roles In regulating plant responses to stress. We Investigated the effects of water stress Induced by adding 12% (w/v) polyethylene glycol to the root medium on the levels of abscisic acid (ABA), indole-3-acid (IAA), zeatin (ZT), and gibberellin3 (GA3) in maize leaves. The results suggested that water stress had significant effects on the four hormone levels. There was a transient increase in the IAA content during the initial stage of adaptation to water stress in maize leaves, but it dropped sharply thereafter in response to water stress. ABA content increased dramatically in maize leaves after 24 h of exposure to water stress, and then the high levels of ABA were maintained to the end, The contents Of ZT and GA3 rapidly declined in maize leaves subjected to water stress. The effects of water stress on chlorophyll content, electrolyte leakage and malondialdehyde levels in maize leaves were also studied. The variation of cell damage was negatively correlated with ZT and GA3 levels in maize leaves under water stress. Thus, we explored the roles of ZT and GA3 on the growth of maize seedlings under water stress by exogenous application. It is possible that both ZT and GA3 were effective in protecting maize seedlings from water stress, which would be of great importance for the improvement of drought tolerance in maize by genetic manipulation.

  12. LOW MOLECULAR WEIGHT O-CARBOXYMETHYLATED CHITOSANS DERIVED FROM IRRADIATED CHITOSAN AND THEIR ANTIBACTERIAL ACTIVITY

    Institute of Scientific and Technical Information of China (English)

    Xu-pin Zhuang; Xiao-fei Liu; Zhi Li; Yun-lin Guan; Kang-de Yao

    2004-01-01

    Original chitosan with My of 2.7 × 10 5 was degraded by irradiation with y-rays and a series of low molecular weight O-carboxymethylated chitosans (O-CMCh) were prepared based on the irradiated chitosan. A kinetic model of the irradiation of chitosan was put forward. Results show that the irradiation degradation of chitosan obeys the rule of random degradation and the degree of deacetylation of irradiated chitosan is slightly raised. The antibacterial activity of O-CMCh is significantly influenced by its MW, and a suppositional antibacterial peak appears when Mv is equal to 2 × 10 5.

  13. Development of a low fat fresh pork sausage based on chitosan with health claims: impact on the quality, functionality and shelf-life.

    Science.gov (United States)

    do Amaral, Deborah S; Cardelle-Cobas, Alejandra; do Nascimento, Bárbara M S; Monteiro, Maria J; Madruga, Marta S; Pintado, Maria Manuela E

    2015-08-01

    A low fat fresh pork sausage based on chitosan was developed with the objective of obtaining a new functional meat product with improved properties and health claims promoting cholesterol reduction. Sausages were formulated with chitosan (2%, w/w) and different fat levels (5%, 12.5% and 20%, w/w). The results indicated that incorporation of 2% chitosan into produced pork sausages with health claims of reduction of cholesterol is technologically feasible. In addition, the chitosan reduced the microbial growth, revealing interesting fat and water absorption capacities, reduced lipid oxidation, provided greater stability in terms of colorimetric parameters and promoted positive firmer texture and gumminess. The reduction of fat content to levels of 5% was positively achieved with the incorporation of chitosan. Sensorial analysis showed that panelists did not detect any significant difference in taste and any unfavorable effect on the sausage appearance as a consequence of chitosan addition and variation of fat.

  14. Uptake of mercury by thiol-grafted chitosan gel beads.

    Science.gov (United States)

    Merrifield, John D; Davids, William G; MacRae, Jean D; Amirbahman, Aria

    2004-07-01

    This study describes the synthesis and characterization of thiol-grafted chitosan beads for use as mercury (Hg) adsorbents. Chitosan flakes were dissolved and formed into spherical beads using a phase inversion technique, then crosslinked to improve their porosity and chemical stability. Cysteine was grafted onto the beads in order to improve the adsorption affinity of Hg to the beads. The beads possessed an average diameter of 3.2 mm, porosity of 0.9, specific surface area of approximately 100 m2/g, average pore size of approximately 120 angstroms, and specific gravity of 2.0. Equilibrium and kinetic uptake experiments were conducted to study the uptake of Hg by the beads. The adsorption capacity was approximately 8.0 mmol-Hg/g-dry beads at pH 7, and decreased with decreasing pH. Hg adsorption kinetics was modeled as radial pore diffusion into a spherical bead with nonlinear adsorption. Use of the nonlinear Freundlich isotherm in the diffusion equation allowed modeling of the uptake kinetics with a single tortuosity factor of 1.5 +/- 0.3 as the fitting parameter for all initial Hg concentrations, chitosan loadings, and agitation rates. At agitation rates of 50 and 75 rpm, where uptake rate was reduced significantly due to the boundary layer effect, the mass transfer coefficient at the outside boundary was also used as a fitting parameter to model the kinetic data. At agitation rates higher than 150 rpm, pore diffusion was the rate-limiting step. The beads exhibited a high initial uptake rate followed by a slower uptake rate suggesting pore diffusion as the rate-determining step especially at high agitation rates. Higher uptake rates observed in this study compared to those in a previous study of chitosan-based crab shells indicate that dissolution and gel formation increase the porosity and pore accessibility of chitosan.

  15. X-Ray Diffraction Studies of Cross Linked Chitosan With Different Cross Linking Agents For Waste Water Treatment Application

    Science.gov (United States)

    Julkapli, Nurhidayatullaili Muhd; Ahmad, Zulkifli; Akil, Hazizan Md

    2010-01-01

    Chitosan is a polysaccharide derived from N-deacetylation of chitin and receiving increased attention as metal ion absorbent in wastewater treatment application. To improve the performance of chitosan as an absorbent, the cross linking approach was applied. Introduction of cross-linking agent would break the crystal zone in chitosan system, making it less crystal and consequently enhanced the absorption area. Therefore, in this study, cross-linked chitosan were prepared using different of cross-linking agents. The chitosan powder was weighed, dissolved in acetic acid (0.1 M), and dropped slowly into absolute N-methyl pyyrolidone solvent containing cross-linking agent. The cross linking reaction was carried out in N2 environment at 150° C for 6 hours. X-ray diffraction (XRD) analysis was applied to characterize the crystallinity of native and cross linked chitosan. Generally, the XRD patterns of all types of chitosan show two crystalline peaks approximately at 10° and 20° (2θ). However, the cross linked chitosan with longer length of cross linking agents show lower and broader crystalline peaks as compare to those with shorter length. Similarly, the calculated crystalline index (Cr I) also showed this decreasing tendency.

  16. Design of chitosan-based nanoparticles functionalized with gallic acid.

    Science.gov (United States)

    Lamarra, J; Rivero, S; Pinotti, A

    2016-10-01

    Active nanoparticles based on chitosan could be applied as a support for the modulation of gallic acid delivery. In this sense, these nanostructures could be employed in different fields such as food, packaging, and pharmaceutical areas. The design parameters of chitosan-based nanoparticles functionalized with gallic acid (GA) were optimized through RSM by means of the analysis of zeta potential (ZP) and percentage encapsulation efficiency (PEE). The nanoparticles were prepared by ionotropic gelation using tripolyphosphate (TPP), at different combinations of chitosan (CH) concentration, CH:TPP ratio and GA. Global desirability methodology allowed finding the optimum formulation that included CH 0.76% (w/w), CH:TPP ratio of 5 and 37mgGA/gCH leading to ZP of +50mV and 82% of PEE. Analysis through QuickScan and turbidity demonstrated that the most stable nanoparticle suspensions were achieved combining concentrations of chitosan ranging between 0.5 and 0.75% with CH:TPP ratios higher than 3. These suspensions had high stability confirmed by means ZP and transmittance values which were higher than +25mV and 0.21 on average, respectively, as well as nanoparticle diameters of about 140nm. FTIR revealed the occurrence of both hydrogen bond and ionic interactions of CH-TPP which allowed the encapsulation and the improvement of the stability of the active agent. PMID:27287172

  17. Novel Chitosan-based Biomaterials

    Institute of Scientific and Technical Information of China (English)

    Mingchun Li; Meihua Xin

    2005-01-01

    @@ 1Introduction Chitosan with two long side chains of N-alkyl group is an important amphiphilic material, which has potential application in tissue engineering and drug delivery system. In this paper the amphiphilic N, N-dilauryl chitosan has been prepared by the phase transfer catalysis. The π-A isotherms of the products were measured in order to find some fundamental data for making self-assembled vesicles out of this kind of material. The LB film experiment indicates that N, N-dilauryl chitosan can form ultrathin LB film with highly ordered layer structure and smooth surface. The thickness of each layer of the LB film was measured as 1.74 nm by XRD.

  18. Maize variety and method of production

    Energy Technology Data Exchange (ETDEWEB)

    Pauly, Markus; Hake, Sarah; Kraemer, Florian J

    2014-05-27

    The disclosure relates to a maize plant, seed, variety, and hybrid. More specifically, the disclosure relates to a maize plant containing a Cal-1 allele, whose expression results in increased cell wall-derived glucan content in the maize plant. The disclosure also relates to crossing inbreds, varieties, and hybrids containing the Cal-1 allele to produce novel types and varieties of maize plants.

  19. In Vitro Biomineralization of Glutaraldehyde Crosslinked Chitosan/Glutamic Acid Films

    Institute of Scientific and Technical Information of China (English)

    FENG Fang; LIU Yu; ZHAO Binyuan; HU Keao

    2009-01-01

    In vitrobiomineralization ofglutaraldehyde crosslinked chitosan/glutamicacid films were studied. IR and ESCA (electron spectroscopy for chemical analysis) determinations confirm that chitosan and glutamic acid are successfully crosslinked by glutaraldehyde to form chitosan-glutamic acid surfaces. Composite films were soaked in saturated Ca(OH)2 solution for 8 d and then immersed in simulated body fluid (SBF) for more than 20 d. Morphological characterizations and structure of cal-cium phosphate coatings deposited on the films were studied by SEM, XRD, and EDAX (energy dispersive X-ray analysis). Initially, the treatment in SBF results in the formation of single-layer cal-cium phosphate particles over the film surface. As immersion time increases, further nucleation and growth produce the simulated calcium-carbonate hydroxyapatite coating. ICP results show Ca/P ratio of calcium phosphate coating is a function of SBF immersion time. The inducing of glutamic acid improves the biomineralization property of chitosan films.

  20. Green synthesis of magnetic chitosan nanocomposites by a new sol-gel auto-combustion method

    Science.gov (United States)

    Ansari, Fatemeh; Sobhani, Azam; Salavati-Niasari, Masoud

    2016-07-01

    The Fe2O3/CuFe2O4/chitosan nanocomposites have been successfully synthesized via a new sol-gel auto-combustion route. To prepare the nanocomposites, copper ferrite (CuFe2O4) and iron (II) oxide (Fe2O3) nanostructures were first prepared utilizing onion as a green reductant for the first time, and characterized by SEM, TEM, XRD, IR and VSM. Then chitosan was added into the nanostructures dispersed in water. Chitosan was used to functionalize and modify the nanostructures and also to improve surface properties. The nanocomposites were also characterized by several techniques including SEM, TEM, XRD, IR and VSM. The effects of amount of onion and chitosan on the morphology and particle size of nanocomposites were evaluated.

  1. Mechanical and dye adsorption properties of graphene oxide/chitosan composite fibers prepared by wet spinning.

    Science.gov (United States)

    Li, Yanhui; Sun, Jiankun; Du, Qiuju; Zhang, Luhui; Yang, Xiaoxia; Wu, Shaoling; Xia, Yanzhi; Wang, Zonghua; Xia, Linhua; Cao, Anyuan

    2014-02-15

    Graphene oxide/chitosan composite fibers were prepared by a wet spinning method, and their mechanical properties were investigated. Experimental results showed that the introduction of graphene oxide at 4 wt% loading can improve the tensile strengths of chitosan fibers. Batch adsorption experiments were carried out to study the effect of various parameters, such as the initial pH value, adsorbent dosage, contact time and temperature on adsorption of fuchsin acid dye. The Langmuir model was used to fit the experimental data of adsorption isotherm, and kinetic studies showed that the adsorption data followed the pseudo-second order model. Thermodynamic studies indicated that the adsorption of fuchsin acid dye on graphene oxide/chitosan fibers was a spontaneous and exothermic process. Our results indicate that the graphene oxide/chitosan fibers have excellent mechanical properties and can serve as a promising adsorbent for the removal of dyes from aqueous solutions. PMID:24507344

  2. Poly (lactic acid)/chitosan fiber mats: investigation of effects of the support on lipase immobilization.

    Science.gov (United States)

    Siqueira, Nataly M; Garcia, Ketlin C; Bussamara, Roberta; Both, Fernanda S; Vainstein, Marilene H; Soares, Rosane M D

    2015-01-01

    The greatest challenge for biotechnological processes is to have immobilized enzymes acting as good green catalysts with high reusability rates. In this work, we have produced electrospun fibers from poly (lactic acid)/chitosan blends. Further, we evaluated the influence of these materials as support for lipase immobilization. The PLA/chitosan fiber mats were composed by non-woven nanofibers, with diameters ranging from 200 nm to 1.3 μm. The solvent (TFA) as well as the chitosan addition influenced morphology, hydrophobicity and mechanical properties of PLA nanofibers. It was observed that even for lower concentration of lipase (5 U) higher enzyme activity retention was detected in the PLA/chitosan blends. In addition, a remarkable improvement of lipase activity on pure PLA fiber mat was verified, indicating that most of the enzymes were probably in their active form. PMID:25290984

  3. Electrorheological Performance of SiO2 Particle Materials of Ce-Doping and Adsorbed Chitosan

    Institute of Scientific and Technical Information of China (English)

    Li Shuxin; Ma Shuzhen; Xu Mingyuan; Shang Yanli; Li Junran; Zhang Shaohua; Zhang Yuanjing; Gao Song

    2004-01-01

    The electrorheological(ER) materials of pure SiO2 ( Sample 1 ), Ce-doping SiO2 ( Ce-SiO2, Sample 2) and Ce-SiO2 adsorbed chitosan (Ce-SiO2-chitosan, Sample 3 ) were prepared using Na2SiO3, Ce( NO3 )3 and chitosan as starting materials. Their ER properties were studied. The results show that Ce-doping can enhance the ER activity of SiO2, and the ER activity of SiO2 can be further improved by adsorbing chitosan on the surfaces of Ce-SiO2 particles.The ER activity of a particle material is correlated with the average grain size, surface area, pore volume and average pore size of the material.

  4. Investigation the Porous Collagen-Chitosan /Glycosaminoglycans for Corneal Cell Culture as Tissue Engineering Scaffold

    Institute of Scientific and Technical Information of China (English)

    LI Qin-Hua; CHEN Jian-Su

    2005-01-01

    The objective of this study was to produce the porous collagen-chitosan/Glycosanminglycans (GAG) for corneal ceil-seed implant as a three-dimensional tissue engineering scaffold to improve the regeneration corneas. The effect of various content of glycerol as form porous agent to collagen-chitosan/GAG preserved a porous dimensional structure was investigated. The heat-drying was used to prepare porous collagen-chitosan /GAG scaffold. The pore morphology of collagenchitosan/GAG was controlled by changing the concentration of glycerol solution and drying methods. The porous structure morphology was observed by SEM. The diameter of the pores form 10 to 50 μm. The highly porous scaffold had interconnecting pores. The corneal cell morphology was observed under the light microscope. These results suggest that collagen-chitosan/GAG showed that corneal cell have formed confluent layers and resemble the surface of normal corneal cell surface.

  5. Evaluation of chitosan quaternary ammonium salt-modified resin denture base material.

    Science.gov (United States)

    Song, Rong; Zhong, Zhaohua; Lin, Lexun

    2016-04-01

    Chitosan quaternary ammonium salt displays good antioxidant and antibacterial characteristics and it shows appreciable solubility in water. When added to the traditional denture material to form a resin base, it could promote good oral health by improving the oral environment. In this study, chitosan quaternary ammonium salt was added to the denture material following two different methods. After three months of immersion in artificial saliva, the specimens were tested for tensile strength and were scanned by electron microscope. The murine fibroblast cytotoxicity and antibacterial properties were also tested. The result showed no significant differences in the tensile strength and in the proliferation of murine L929 fibroblast cells. The two structures of chitosan quaternary ammonium salt-modified denture material had different degrees of corrosion resistance and antimicrobial properties. These results indicate that chitosan quaternary ammonium salt-modified resin denture base material has the potential to become a new generation oral denture composite material.

  6. Effects of laminin blended with chitosan on axon guidance on patterned substrates

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, N; Guan, Y J; Chen, X B [Division of Biomedical Engineering, University of Saskatchewan, Saskatoon S7N 5A9 (Canada); Li, M G [Department of Mechanical Engineering, University of Saskatchewan, Saskatoon S7N 5A9 (Canada); Schreyer, D J, E-mail: niz504@mail.usask.c [Department of Anatomy and Cell Biology, Cameco MS Neuroscience Research Center, University of Saskatchewan, Saskatoon, S7K 0M7 (Canada)

    2010-12-15

    Axon guidance is a crucial consideration in the design of tissue scaffolds used to promote nerve regeneration. Here we investigate the combined use of laminin (a putative axon adhesion and guidance molecule) and chitosan (a leading candidate base material for the construction of scaffolds) for promoting axon guidance in cultured adult dorsal root ganglion (DRG) neurons. Using a dispensing-based rapid prototyping (DBRP) technique, two-dimensional grid patterns were created by dispensing chitosan or laminin-blended chitosan substrate strands oriented in orthogonal directions. In vitro experiments illustrated DRG neurites on these patterns preferentially grew upon and followed the laminin-blended chitosan pathways. These results suggest that an orientation of neurite growth can be achieved in an artificially patterned substrate by creating selectively biofunctional pathways. The DBRP technique may provide improved strategies for the use of biofunctional pathways in the design of three-dimensional scaffolds for guidance of nerve repair.

  7. Applying CSM-CERES-Maize to define a sowing window for irrigated maize crop - The Riacho´s Farm case study

    Directory of Open Access Journals (Sweden)

    Denise Freitas Silva

    2011-08-01

    Full Text Available Irrigation use constitutes an alternative to improve maize production in Central Minas Gerais State, Brazil. However, even under adequate water supply conditions, other environmental factors may influence maize crop growth and development and may, ultimately, affect grain yield. This study aimed to establish a sowing window for irrigated maize crop, based on simulation results obtained with the decision support model CSM-CERES-Maize. Simulations were made for crop management conditions of Riacho´s Farm, located in Matozinhos, Minas Gerais State, Brazil. It was employed the model´s seasonal tool, along with a data set containing 46 years of weather data records, to simulate maize yield for weekly sowing scenarios, starting on August 1st and ending on July 24th of each year. One defined an irrigated maize sowing window, taking into account the yield break risk that a farmer would be willing to take. The model proved to be an interesting tool to assist in decision making, regarding crop and irrigation management, for an irrigated maize production system. Assuming a 10% yield break in the expected average maximum maize yield, it was defined as sowing window, the period from January 23rd to March 6th, with February 20th as the best sowing date. Other sowing windows may be established according to the risk that the farmer would be willing to take.

  8. A study on biosorption of copper ions by fungal chitosan: an alternative to shrimp chitosan

    Directory of Open Access Journals (Sweden)

    Sanaz Behnam

    2015-02-01

    Full Text Available   Introduction : One of the main applications of chitosan is for heavy metals removal from waste waters. Industrially, chitosan is produced through deacetylation of chitin present in shellfish waste. Another source of chitosan is the cell wall of zygomycetes fungi with several advantages over shellfish wastes .   Materials and method s: Fungal chitosan purified from biomass of Mucor indicus and shrimp chitosan were applied and compared for removal of copper ions from aqueous solution. The effects of pH (3 to 5.5, copper ion concentration (5 to 52 mg l-1, the amount of chitosan (200 to 3000 mg l-1, adsorption time, temperature, and presence of other metal ions on the biosorption of Cu2+ were investigated .   Results : Maximum adsorption capacities for fungal and shrimp chitosans were 58.5 and 60.7 mg g-1, respectively. T he rate of copper adsorption by the fungal chitosan was significantly higher than that by the shrimp chitosan. Among p seudo-first order, pseudo-second order, intra-particle diffusion, and Elovich models, Ho’s pseudo-second order model was the best model for fitting the kinetic data. The adsorption capacity increased for both types of chitosans by increasing the solution pH. However, temperature and presence of other ions did not show significant effects on the biosorption capacity of copper. The isotherm data were very well described by Langmuir, Freundlich, and Redlich-Peterson models .   Discussion and conclusion : Both fungal and shrimp chitosans can effectively be used for removal of copper ions from aqueous solutions. Adsorption process for fungal chitosan is fast, while the process is slower for the shrimp chitosan. Therefore, from the kinetics point of view, the fungal chitosan is preferable compared with the shrimp chitosan . Key words: Biosorption, Copper, Fungal chitosan, Shrimp chitosan, Water treatment .

  9. A study on the performance of hyaluronic acid immobilized chitosan film

    Energy Technology Data Exchange (ETDEWEB)

    Wang Yingjun; Guo Li; Ren Li; Yin Shiheng [Biomaterial Research Institute, College of Material Science and Engineering, South China University of Technology, Guangzhou, 510640 (China); Ge Jian; Gao Qianying [State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, 510060 (China); Luxbacher, Thomas; Luo Shijing, E-mail: imwangyj@scut.edu.c, E-mail: psliren@scut.edu.c [Anton Paar GmbH, Anton-Paar-Strasse 20, A-8054 Graz (Austria)

    2009-06-15

    In order to improve hydrophilicity and biocompatibility of chitosan, hyaluronic acid was immobilized onto the surface of chitosan film. The structure of films was characterized by Fourier transformed infrared spectroscopy with attenuated total reflectance (ATR-FTIR), x-ray photoelectron spectroscopy (XPS) and zeta potential. Results confirmed that hyaluronic acid was successfully immobilized on chitosan film. Transparency, water absorption percentage and contact angle of films were characterized. Results showed that there was no significant variation in transparency (p < 0.05) before and after immobilization, the maximum was up to 99% which was enough for corneal regeneration in clinical applications. After the immobilization, the time-dependent contact angle declined sharply (from 91.8 deg. to 67.7 deg. at 100 s). The hydrophilicity was significantly improved. The methylthiazol tetrazolium (MTT) (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assay was used to assess cell viability and proliferation. Results showed that human cornea epithelial cells (HCEC) grew better on hyaluronic acid immobilized chitosan films than on chitosan films. The hyaluronic acid immobilized chitosan film could be a promising candidate material for corneal regeneration.

  10. Preparation and characterisation of new-polyaluminum chloride-chitosan composite coagulant.

    Science.gov (United States)

    Ng, Mega; Liana, Ayu E; Liu, Sanly; Lim, May; Chow, Christopher W K; Wang, Dongsheng; Drikas, Mary; Amal, Rose

    2012-10-01

    In this study, the formulation of a novel polyaluminum chloride-chitosan composite coagulant that improves the coagulation process for natural organic matter (NOM) removal was investigated. The performance of the composite coagulant was tested using two water sources (synthetic and natural water) to develop a better understanding on the behaviour of the composite coagulant. Fourier Transform-Infra red (FT-IR) spectroscopy, ferron analysis and zeta potential studies were performed to characterise the composite coagulant. FT-IR analysis showed that there is an intermolecular interaction between Al species and chitosan molecules, while ferron analysis indicated that the distributions of Al(a), Al(b), and Al(c) in PACl-chitosan are different from those in PACl. At a low Al dosage (2.16 mg L⁻¹), a much higher removal of NOM from synthetic water, as evidenced from UV₂₅₄ and Dissolved Organic Carbon (DOC) measurements, was achieved by the composite coagulants in comparison to that removed by PACl or PACl and chitosan added separately. For natural water from the Myponga Reservoir, both polyaluminum chloride (PACl) and PACl-chitosan composite coagulants demonstrated similar dissolved organic carbon (DOC) percentage removal, whereas PACl-chitosan gave a slight improvement in removing the UV₂₅₄ absorbing components of NOM.

  11. Microbial enhance of chitosan production by Rhizopus arrhizus using agroindustrial substrates.

    Science.gov (United States)

    Cardoso, Antonio; Lins, Clarissa Izabel M; dos Santos, Ednaldo Ramos; Freitas Silva, Marta C; Campos-Takaki, Galba M

    2012-01-01

    This study investigated the potential of Rhizopus arrhizus UCP 402 for producing chitosan using corn steep liquor and honey as agroindustrial nitrogen and carbon sources. A complete factorial design was used to assess the improved biomass and chitosan production. The results were evaluated using Pareto charts (Statistica 7.0 software). The chitosan obtained was characterized by X-ray diffraction. The cristallinity index (I(C)), and infrared spectroscopy (FTIR) were used to evaluate the degree of deacetylation (DD %). The morphological aspects of the R. arrhizus were evaluated by measuring the diameter of the colonies by light microscopy. The results obtained showed higher biomass and chitosan yields (20.61 g/L and 29.3 mg/g), respectively, in the selected assays. The characterization of the macromolecular arrangement of chitosan showed a crystallinity index compatible with the literature, and the infrared peaks confirmed a degree of 86%. The experimental data obtained suggest that adding honey to corn steep liquor is a promising way to improve microbiological chitosan production. PMID:22543505

  12. Microbial Enhance of Chitosan Production by Rhizopus arrhizus Using Agroindustrial Substrates

    Directory of Open Access Journals (Sweden)

    Marta C. Freitas Silva

    2012-04-01

    Full Text Available This study investigated the potential of Rhizopus arrhizus UCP 402 for producing chitosan using corn steep liquor and honey as agroindustrial nitrogen and carbon sources. A complete factorial design was used to assess the improved biomass and chitosan production. The results were evaluated using Pareto charts (Statistica 7.0 software. The chitosan obtained was characterized by X-ray diffraction. The cristallinity index (IC, and infrared spectroscopy (FTIR were used to evaluate the degree of deacetylation (DD %. The morphological aspects of the R. arrhizus were evaluated by measuring the diameter of the colonies by light microscopy. The results obtained showed higher biomass and chitosan yields (20.61 g/L and 29.3 mg/g, respectively, in the selected assays. The characterization of the macromolecular arrangement of chitosan showed a crystallinity index compatible with the literature, and the infrared peaks confirmed a degree of 86%. The experimental data obtained suggest that adding honey to corn steep liquor is a promising way to improve microbiological chitosan production.

  13. Microbial Enhance of Chitosan Production by Rhizopus arrhizus Using Agroindustrial Substrates

    Directory of Open Access Journals (Sweden)

    Marta C. Freitas Silva

    2012-04-01

    Full Text Available This study investigated the potential of Rhizopus arrhizus UCP 402 for producing chitosan using corn steep liquor and honey as agroindustrial nitrogen and carbon sources. A complete factorial design was used to assess the improved biomass and chitosan production. The results were evaluated using Pareto charts (Statistica 7.0 software. The chitosan obtained was characterized by X-ray diffraction. The cristallinity index (IC, and infrared spectroscopy (FTIR were used to evaluate the degree of deacetylation (DD %. The morphological aspects of the R. arrhizus were evaluated by measuring the diameter of the colonies by light microscopy. The results obtained showed higher biomass and chitosan yields (20.61 g/L and 29.3 mg/g, respectively, in the selected assays. The characterization of the macromolecular arrangement of chitosan showed a crystallinity index compatible with the literature, and the infrared peaks confirmed a degree of 86%. The experimental data obtained suggest that adding honey to corn steep liquor is a promising way to improve microbiological chitosan production.

  14. Effect of chitosan and thiolated chitosan coating on the inhibition behaviour of PIBCA nanoparticles against intestinal metallopeptidases

    International Nuclear Information System (INIS)

    Surface modified nanoparticles composed of poly(isobutylcyanoacrylate) (PIBCA) cores surrounded by a chitosan and thiolated chitosan gel layer were prepared and characterized in previous works. The presence of such biopolymers on the nanoparticle surface conferred those nanosystems interesting characteristics that might partially overcome the gastrointestinal enzymatic barrier, improving the oral administration of pharmacologically active peptides. In the present work, the antiprotease behaviour of this family of core-shell nanoparticles was in vitro tested against two model metallopeptidases present in the gastrointestinal tract (GIT): Carboxypeptidase A -CP A- (luminal protease) and Leucine Aminopeptidase M -LAP M- (membrane protease). As previous step, the zinc-binding capacity of these nanoparticles was evaluated. Interestingly, an improvement of both the zinc-binding capacity and the antiprotease effect of chitosan was observed when the biopolymers (chitosan and thiolated chitosan) were used as coating component of the core-shell nanoparticles, in comparison with their behaviour in solution, thanks to the different biopolymer chains rearrangement. The presence of amino, hydroxyl and thiol groups on the nanoparticle surface promoted zinc binding and hence the inhibition of the metallopeptidases analysed. On the contrary, the occurrence of a cross-linked structure in the gel layer surrounding the PIBCA cores of thiolated formulations, due to the formation of interchain and intrachain disulphide bonds, partially limited the inhibition of the proteases. The low accessibility of cations to the active groups of the cross-linked polymeric shell was postulated as a possible explanation of this behaviour. Results obtained in this work make this family of surface-modified nanocarriers promising candidates for the successfull administration of pharmacologically active peptides and proteins by the oral route.

  15. Determination of physical properties for β-TCP + chitosan biomaterial obtained on metallic 316L substrates

    Energy Technology Data Exchange (ETDEWEB)

    Mina, A. [Tribology, Powder Metallurgy and Processing of Solid Recycled Research Group, Universidad del Valle, Cali (Colombia); Tecno-Academia ASTIN SENA Reginal Valle (Colombia); Castaño, A. [Tribology, Powder Metallurgy and Processing of Solid Recycled Research Group, Universidad del Valle, Cali (Colombia); Caicedo, J.C., E-mail: julio.cesar.caicedo@correo.univalle.edu.co [Tribology, Powder Metallurgy and Processing of Solid Recycled Research Group, Universidad del Valle, Cali (Colombia); Caicedo, H.H. [Biologics Research, Biotechnology Center of Excellence, Janssen R& D, LLC, Pharmaceutical Companies of Johnson & Johnson, Spring House, PA 19477 (United States); National Biotechnology & Pharmaceutical Association, Chicago, IL 60606 (United States); Aguilar, Y. [Tribology, Powder Metallurgy and Processing of Solid Recycled Research Group, Universidad del Valle, Cali (Colombia)

    2015-06-15

    Material surface modification, particularly the deposition of special coatings on the surface of surgical implants, is extensively used in bone tissue engineering applications. β-Tricalcium phosphate/Chitosan (β-TCP/Ch) coatings were deposited on 316L stainless steel (316L SS) substrates by a cathodic electro-deposition technique at different coating compositions. The crystal lattice arrangements were analyzed by X-Ray diffraction (XRD), and the results indicated that the crystallographic structure of β-TCP was affected by the inclusion of the chitosan content. The changes in the surface morphology as a function of increasing chitosan in the coatings via scanning electron microscopy (SEM) and atomic force microscopy (AFM) showed that root-mean square values of the β-TCP/Ch coatings decreased by further increasing chitosan percentage. The elastic–plastic characteristics of the coatings were determined by conducting nanoindentation test, indicating that increase of chitosan percentage is directly related to increase of hardness and elastic modulus of the β-TCP/Ch coatings. Tribological characterization was performed by scratch test and pin-on-disk test to analyze the changes in the surface wear of β-TCP/Ch coatings. Finally, the results indicated an improvement in the mechanical and tribological properties of the β-TCP/Ch coatings as a function of increasing of the chitosan percentage. This new class of coatings, comprising the bioactive components, is expected not only to enhance the bioactivity and biocompatibility, but also to protect the surface of metallic implants against wear and corrosion. - Highlights: • Superficial phenomenon that occurs in tribological surface of β-tricalcium phosphate-chitosan coatings. • Improvement on surface mechanical properties of ceramic-polymeric and response to surface tribological damage. • β-tricalcium phosphate-chitosan coatings that offer highest performance in the biomedical devices.

  16. Thiolated chitosan-modified PLA-PCL-TPGS nanoparticles for oral chemotherapy of lung cancer

    Science.gov (United States)

    Jiang, Liqin; Li, Xuemin; Liu, Lingrong; Zhang, Qiqing

    2013-02-01

    Oral chemotherapy is a key step towards `chemotherapy at home', a dream of cancer patients, which will radically change the clinical practice of chemotherapy and greatly improve the quality of life of the patients. In this research, three types of nanoparticle formulation from commercial PCL and self-synthesized d-α-tocopheryl polyethylene glycol 1000 succinate (PLA-PCL-TPGS) random copolymer were prepared in this research for oral delivery of antitumor agents, including thiolated chitosan-modified PCL nanoparticles, unmodified PLA-PCL-TPGS nanoparticles, and thiolated chitosan-modified PLA-PCL-TPGS nanoparticles. Firstly, the PLA-PCL-TPGS random copolymer was synthesized and characterized. Thiolated chitosan greatly increases its mucoadhesiveness and permeation properties, thus increasing the chances of nanoparticle uptake by the gastrointestinal mucosa and improving drug absorption. The PLA-PCL-TPGS nanoparticles were found by FESEM that they are of spherical shape and around 200 nm in diameter. The surface charge of PLA-PCL-TPGS nanoparticles was reversed from anionic to cationic after thiolated chitosan modification. The thiolated chitosan-modified PLA-PCL-TPGS nanoparticles have significantly higher level of the cell uptake than that of thiolated chitosan-modified PLGA nanoparticles and unmodified PLA-PCL-TPGS nanoparticles. In vitro cell viability studies showed advantages of the thiolated chitosan-modified PLA-PCL-TPGS nanoparticles over Taxol® in terms of cytotoxicity against A549 cells. It seems that the mucoadhesive nanoparticles can increase paclitaxel transport by opening tight junctions and bypassing the efflux pump of P-glycoprotein. In conclusion, PLA-PCL-TPGS nanoparticles modified by thiolated chitosan could enhance the cellular uptake and cytotoxicity, which revealed a potential application for oral chemotherapy of lung cancer.

  17. Determination of physical properties for β-TCP + chitosan biomaterial obtained on metallic 316L substrates

    International Nuclear Information System (INIS)

    Material surface modification, particularly the deposition of special coatings on the surface of surgical implants, is extensively used in bone tissue engineering applications. β-Tricalcium phosphate/Chitosan (β-TCP/Ch) coatings were deposited on 316L stainless steel (316L SS) substrates by a cathodic electro-deposition technique at different coating compositions. The crystal lattice arrangements were analyzed by X-Ray diffraction (XRD), and the results indicated that the crystallographic structure of β-TCP was affected by the inclusion of the chitosan content. The changes in the surface morphology as a function of increasing chitosan in the coatings via scanning electron microscopy (SEM) and atomic force microscopy (AFM) showed that root-mean square values of the β-TCP/Ch coatings decreased by further increasing chitosan percentage. The elastic–plastic characteristics of the coatings were determined by conducting nanoindentation test, indicating that increase of chitosan percentage is directly related to increase of hardness and elastic modulus of the β-TCP/Ch coatings. Tribological characterization was performed by scratch test and pin-on-disk test to analyze the changes in the surface wear of β-TCP/Ch coatings. Finally, the results indicated an improvement in the mechanical and tribological properties of the β-TCP/Ch coatings as a function of increasing of the chitosan percentage. This new class of coatings, comprising the bioactive components, is expected not only to enhance the bioactivity and biocompatibility, but also to protect the surface of metallic implants against wear and corrosion. - Highlights: • Superficial phenomenon that occurs in tribological surface of β-tricalcium phosphate-chitosan coatings. • Improvement on surface mechanical properties of ceramic-polymeric and response to surface tribological damage. • β-tricalcium phosphate-chitosan coatings that offer highest performance in the biomedical devices

  18. Zwitterionic chitosan derivatives for pH-sensitive stealth coating

    OpenAIRE

    Xu, Peisheng; Bajaj, Gaurav; Shugg, Tyler; Van Alstine, William G.; Yeo, Yoon

    2010-01-01

    Zwitterionic chitosan, a chitosan derivative with a unique pH-dependent charge profile, was employed to create a stealth coating on the cationic surface of drug carriers. Zwitterionic chitosans were synthesized by amidation of chitosan with succinic anhydride. The succinic anhydride-conjugated chitosan had an isoelectric point, which could be easily tuned from pH 4.9 to 7.1, and showed opposite charges below and above the isoelectric point. The succinic anhydride-conjugated chitosan was able ...

  19. Chitosan as a starting material for wound healing applications

    OpenAIRE

    Patrulea, Viorica; Ostafe, V.; Borchard, Gerrit; Jordan, Olivier

    2015-01-01

    Chitosan and its derivatives have attracted great attention due to their properties beneficial for application to wound healing. The main focus of the present review is to summarize studies involving chitosan and its derivatives, especially N,N,N-trimethyl-chitosan (TMC), N,O-carboxymethyl-chitosan (CMC) and O-carboxymethyl-N,N,N-trimethyl-chitosan (CMTMC), used to accelerate wound healing. Moreover, formulation strategies for chitosan and its derivatives, as well as their in vitro, in vivo a...

  20. Pharmacokinetics and biodegradation of chitosan in rats

    Science.gov (United States)

    Li, Hui; Jiang, Zhiwen; Han, Baoqin; Niu, Shuyi; Dong, Wen; Liu, Wanshun

    2015-10-01

    Chitosan, an excellent biomedical material, has received a widespread in vivo application. In contrast, its metabolism and distribution once being implanted were less documented. In this study, the pharmacokinetics and biodegradation of fluorescein isothiocyanate (FITC) labeled and muscle implantation administrated chitosan in rats were investigated with fluorescence spectrophotometry, histological assay and gel chromatography. After implantation, chitosan was degraded gradually during its distribution to diverse organs. Among the tested organs, liver and kidney were found to be the first two highest in chitosan content, which was followed by heart, brain and spleen. Urinary excretion was believed to be the major pathway of chitosan elimination, yet 80% of chitosan administered to rats was not trackable in their urine. This indicated that the majority of chitosan was degraded in tissues. In average, the molecular weight of the degradation products of chitosan in diverse organs and urine was found to be <65 kDa. This further confirmed the in vivo degradation of chitosan. Our findings provided new evidences for the intensive and safe application of chitosan as a biomedical material.

  1. Chitin, Chitosan, and Glycated Chitosan Regulate Immune Responses: The Novel Adjuvants for Cancer Vaccine

    OpenAIRE

    Xiaosong Li; Min Min; Nan Du; Ying Gu; Tomas Hode; Mark Naylor; Dianjun Chen; Nordquist, Robert E.; Chen, Wei R.

    2013-01-01

    With the development of cancer immunotherapy, cancer vaccine has become a novel modality for cancer treatment, and the important role of adjuvant has been realized recently. Chitin, chitosan, and their derivatives have shown their advantages as adjuvants for cancer vaccine. In this paper, the adjuvant properties of chitin and chitosan were discussed, and some detailed information about glycated chitosan and chitosan nanoparticles was also presented to illustrate the trend for future development.

  2. Chitosan and chitosan/wheat gluten blends : properties of extrudates, solid films and bio-foams

    OpenAIRE

    Chen, Fei

    2015-01-01

    This thesis presents four different studis describing the characteristics and processing opportunities of two widely available biopolymers: chitosan and wheat gluten. The interest in these materials is mainly because they are bio-based and obtained as co- or by-products in the fuel and food sector In the first study, high solids content chitosan samples (60 wt.%) were successfully extruded. Chitosan extrusion has previously been reported but not chitosan extrusion with a high solids content, ...

  3. Performance of a local open pollinated maize variety and a common hybrid variety under intensive small-scale farming practices

    OpenAIRE

    Norton, J B.; Omondi, E.C.; Ashilenje, Dennis S.

    2014-01-01

    Metadata only record Given that the majority of maize farmers in Kenya are small-scale, improvement in maize production must focus on increased production per unit area. While hybrid maize varieties outperform local open pollinated varieties under conventional farming practices, their relative performance has not been tested under small-scale intensive production practices. A study was conducted in 2013 in Kitale, western Kenya, to evaluate performance of ‘Namba Nane’; a local open pollina...

  4. Chitosan adsorption to salivary pellicles

    NARCIS (Netherlands)

    van der Mei, Henderina; Engels, Eefje; de Vries, Jacob; Dijkstra, Rene JB; Busscher, Hendrik

    2007-01-01

    The salivary pellicle is a negatively charged protein film, to which oral bacteria readily adhere. Chitosans are cationic biomolecules with known antimicrobial properties that can be modified in different ways to enhance its antimicrobial activity. Here, we determined the changes in surface chemical

  5. Effects of electrospun chitosan wrapping for dry-ageing of beef, as studied by microbiological, physicochemical and low-field nuclear magnetic resonance analysis

    DEFF Research Database (Denmark)

    Guðjónsdóttir, María; Gacutan, Manuel D.; Mendes, Ana Carina Loureiro;

    2015-01-01

    The effects of using electrospun chitosan fibres as a wrapping material for dry-ageing beef was studied and compared to traditional dry-ageing and wet-ageing of beef for up to 21 days. The chitosan treatment showed improved results in terms of yield, reduction of microbial counts, yeasts and moul...

  6. Chitosan and carboxymethyl-chitosan capping ligands: Effects on the nucleation and growth of hydroxyapatite nanoparticles for producing biocomposite membranes.

    Science.gov (United States)

    Dumont, Vitor C; Mansur, Alexandra A P; Carvalho, Sandhra M; Medeiros Borsagli, Fernanda G L; Pereira, Marivalda M; Mansur, Herman S

    2016-02-01

    phosphate phase produced during the co-precipitation aqueous process for both the chitosan and CMC biocomposites. These novel hybrid systems based on chitosan and chitosan-derivatives with nHA composites were non-cytotoxic to a human osteoblast-like model cell line (SAOS) according to MTT in vitro assays. Moreover, the CMC-nHA biocomposites revealed a striking improvement in the cell viability response compared to the CHI-nHA biocomposite, which was attributed to the much higher surface area caused by the refinement of the nanoparticles size. Thus, the results of this study demonstrate that these novel bionanocomposite membranes offer promising perspectives as biomaterials for potential repair and replacement of cartilage and bone tissues. PMID:26652373

  7. A rapid and efficient method for assessing pathogenicity of ustilago maydis on maize and teosinte lines.

    Science.gov (United States)

    Chavan, Suchitra; Smith, Shavannor M

    2014-01-03

    Maize is a major cereal crop worldwide. However, susceptibility to biotrophic pathogens is the primary constraint to increasing productivity. U. maydis is a biotrophic fungal pathogen and the causal agent of corn smut on maize. This disease is responsible for significant yield losses of approximately $1.0 billion annually in the U.S.(1) Several methods including crop rotation, fungicide application and seed treatments are currently used to control corn smut(2). However, host resistance is the only practical method for managing corn smut. Identification of crop plants including maize, wheat, and rice that are resistant to various biotrophic pathogens has significantly decreased yield losses annually(3-5). Therefore, the use of a pathogen inoculation method that efficiently and reproducibly delivers the pathogen in between the plant leaves, would facilitate the rapid identification of maize lines that are resistant to U. maydis. As, a first step toward indentifying maize lines that are resistant to U. maydis, a needle injection inoculation method and a resistance reaction screening method was utilized to inoculate maize, teosinte, and maize x teosinte introgression lines with a U. maydis strain and to select resistant plants. Maize, teosinte and maize x teosinte introgression lines, consisting of about 700 plants, were planted, inoculated with a strain of U. maydis, and screened for resistance. The inoculation and screening methods successfully identified three teosinte lines resistant to U. maydis. Here a detailed needle injection inoculation and resistance reaction screening protocol for maize, teosinte, and maize x teosinte introgression lines is presented. This study demonstrates that needle injection inoculation is an invaluable tool in agriculture that can efficiently deliver U. maydis in between the plant leaves and has provided plant lines that are resistant to U. maydis that can now be combined and tested in breeding programs for improved disease resistance.

  8. Proton play in the formation of low molecular weight chitosan (LWCS) by hydrolyzing chitosan with a carbon based solid acid.

    Science.gov (United States)

    Krishnan, R Akhil; Deshmukh, Pranjal; Agarwal, Siddharth; Purohit, Poorvi; Dhoble, Deepa; Waske, Prashant; Khandekar, Dileep; Jain, Ratnesh; Dandekar, Prajakta

    2016-10-20

    Low molecular weight chitosan (LWCS) constitute a special class of value added chemicals that are primarily obtained from crustacean shells, which are the main water pollutants from crabs and shrimp processing centers. Unlike chitin and chitosan, LWCS possess improved solubility in water and aqueous solutions, making them widely applicable in numerous fields ranging from drug delivery to waste water treatment. Among the methods employed for their production, chemical breakdown by strong liquid acids has yielded good success. However, this method is met with severe concerns arising from the harsh nature of liquid acids, which may corrode the reactors for commercial synthesis, and their limited reusability. The physical methods like ultrasound and microwave are energy intensive in nature, while the enzymatic methods are expensive and offers limited scope for reuse. We have attempted to overcome these problems by employing carbon based solid acid (CSA) for hydrolyzing chitosan to LWCS. CSA can be easily produced using activated carbon, a cost-effective and easily available raw material. Reactions were carried out between chitosan and CSA in a hydrothermal glass reactor and the products, separated by cold centrifugation, were purified and dried. The dried products were characterized for their molecular weight and solubility. Results indicated more than ten-fold decrease in the molecular weight of chitosan and the product exhibited water solubility. The CSA could be used upto four times, without regeneration, to give a consistent quality product. The aqueous solution of resulting LWCS exhibited a pH of 6.03±0.11, as against the acidic pH range of solutions of commercially available LWCS, indicating its suitability for biomedical applications. Our investigation facilitates a 'green approach' that may be employed for commercial production of value added chemicals from waste products of marine industry. PMID:27474584

  9. Chitosan-praseodymium complex for adsorption of fluoride ions from water

    Institute of Scientific and Technical Information of China (English)

    Eny Kusrini; Nofrijon Sofyan; Nyoman Suwartha; Gefin Yesya; Cindy Rianti Priadi

    2015-01-01

    Engineering of chitosan by praseodymium has been investigated to improve the adsorption properties as well as physical characteristics of chitosan. Modification of chitosan changes the original properties of chitosan so that it can be more suitable for ad-sorption of fluoride ions. In this study, chitosan-praseodymium (Chi-Pr) was synthesized by impregnation method. The Chi-Pr com-plex was characterized by scanning electron microscopic-energy dispersive X-ray spectroscopy (SEM-EDX), Fourier transform in-frared (FTIR) and employed as an adsorbent for removal of fluorides ions from water in the batch system. The variables such as con-tact time, concentration of Pr, adsorbent dose, initial concentration of fluoride ions, and competitor anions were studied. The adsorp-tion efficiency of fluoride ions (η) with increasing Pr loading into chitosan (5 wt.%, 10 wt.%, 15 wt.%, 20 wt.% and 25 wt.%) were 35.5%, 56.1%, 72.0%, 68.5% and 62.5%, respectively. The Chi-Pr (15 wt.%) complex had the highest fluoride removal efficiency (72.0%). The experimental data fitted well to the Langmuir isotherm with maximum adsorption capacity (qmax) of 15.87 mg/g and an equilibrium constant (kL) of 0.15 mg. Kinetic study revealed that the adsorption of fluoride ions from water followed pseudo-second-order model with a maximum adsorption capacity (q2) of 8.20 mg/g and a rate constant (k2) of 0.01 g/mg·min. Ad-sorption efficiency of fluoride ions in the simulated drinking water was diminished with the changes in pH levels. The presence of Pr3+in chitosan increased chitosan's performance as an adsorbent for adsorption of fluoride ions.

  10. Flexible bactericidal graphene oxide–chitosan layers for stem cell proliferation

    Energy Technology Data Exchange (ETDEWEB)

    Mazaheri, M. [Department of Materials Science and Engineering, Sharif University of Technology, PO Box 11365-9466, Tehran (Iran, Islamic Republic of); Akhavan, O., E-mail: oakhavan@sharif.edu [Department of Physics, Sharif University of Technology, PO Box 11155-9161, Tehran (Iran, Islamic Republic of); Institute for Nanoscience and Nanotechnology, Sharif University of Technology, PO Box 14588-89694, Tehran (Iran, Islamic Republic of); Simchi, A. [Department of Materials Science and Engineering, Sharif University of Technology, PO Box 11365-9466, Tehran (Iran, Islamic Republic of); Institute for Nanoscience and Nanotechnology, Sharif University of Technology, PO Box 14588-89694, Tehran (Iran, Islamic Republic of)

    2014-05-01

    Highlights: • Fabrication of flexible graphene oxide–chitosan nanocomposite layers was reported. • The flexibility of the chitosan layers were improved by adding graphene oxide sheets. • The nanocomposite layers with 1.5 wt% graphene oxide content showed yielded flexible and antibacterial surfaces for stem cell proliferation. - Abstract: Graphene oxide (GO)–chitosan composite layers with stacked layer structures were synthesized using chemically exfoliated GO sheets (with lateral dimensions of ∼1 μm and thickness of ∼1 nm), and applied as antibacterial and flexible nanostructured templates for stem cell proliferation. By increasing the GO content from zero to 6 wt%, the strength and elastic modulus of the layers increased ∼80% and 45%, respectively. Similar to the chitosan layer, the GO–chitosan composite layers showed significant antibacterial activity (>77% inactivation after only 3 h) against Staphylococcus aureus bacteria. Surface density of the actin cytoskeleton fibers of human mesenchymal stem cells (hMSCs) cultured on the chitosan and GO(1.5 wt%)–chitosan composite layers was found nearly the same, while it significantly decreased by increasing the GO content to 3 and 6 wt%. Our results indicated that although a high concentration of GO in the chitosan layer (here, 6 wt%) could decelerate the proliferation of the hMSCs on the flexible layer, a low concentration of GO (i.e., 1.5 wt%) not only resulted in biocompatibility but also kept the mechanical flexibility of the self-sterilized layers for high proliferation of hMSCs.

  11. Preparation and Application of Chitosan Membranes to Filter Silver from X-ray Film Processing Wastes

    Science.gov (United States)

    Nyoman Rupiasih, N.; Rustam Purnomo, Rendra; Sumadiyasa, Made

    2016-04-01

    Chitosan is a natural polysaccharide biopolymer which has been widely used in different processes and applications. Chitosan based membranes have been used in reverse osmosis, gas separation, dialysis and pervaporation. The object of this research was investigating the possibility of chitosan membrane used as a filter for removing silver (Ag) from X-ray film processing wastes. Several of chitosan membranes such as M1, M2, M3 and M4 have been prepared for the purpose and filtration was done using dead-end filtration method. The filtration experiments were performed on a flat sheet membrane using pure water and X-ray film processing wastes as feeds. The analysis of silver concentration has been done by atomic absorption spectrometers (AAS). The results show that chitosan membrane M2 gave the highest filtration coefficient (Rcoeff ) i.e. 99.9%, with the pure water flux (PWF) and product flux (PF) are 2972.56 L/m2h and 1761.18 L/m2h respectively. The rejection coefficient of the membranes decreases with increasing the amount of chitosan, while the pure water flux and product flux are increased. The filtration coefficients show that the chitosan membranes are able to filter silver waste from X-ray film processing wastes with performance dependent on their characteristic such as pores size. This suggests that, chitosan membrane can be used as one method that is safe and friendly environment for recovering silver from X-ray film processing waste to improve the quality of treated to an acceptable quality level.

  12. Flexible bactericidal graphene oxide–chitosan layers for stem cell proliferation

    International Nuclear Information System (INIS)

    Highlights: • Fabrication of flexible graphene oxide–chitosan nanocomposite layers was reported. • The flexibility of the chitosan layers were improved by adding graphene oxide sheets. • The nanocomposite layers with 1.5 wt% graphene oxide content showed yielded flexible and antibacterial surfaces for stem cell proliferation. - Abstract: Graphene oxide (GO)–chitosan composite layers with stacked layer structures were synthesized using chemically exfoliated GO sheets (with lateral dimensions of ∼1 μm and thickness of ∼1 nm), and applied as antibacterial and flexible nanostructured templates for stem cell proliferation. By increasing the GO content from zero to 6 wt%, the strength and elastic modulus of the layers increased ∼80% and 45%, respectively. Similar to the chitosan layer, the GO–chitosan composite layers showed significant antibacterial activity (>77% inactivation after only 3 h) against Staphylococcus aureus bacteria. Surface density of the actin cytoskeleton fibers of human mesenchymal stem cells (hMSCs) cultured on the chitosan and GO(1.5 wt%)–chitosan composite layers was found nearly the same, while it significantly decreased by increasing the GO content to 3 and 6 wt%. Our results indicated that although a high concentration of GO in the chitosan layer (here, 6 wt%) could decelerate the proliferation of the hMSCs on the flexible layer, a low concentration of GO (i.e., 1.5 wt%) not only resulted in biocompatibility but also kept the mechanical flexibility of the self-sterilized layers for high proliferation of hMSCs

  13. In vitro and in vivo Characterization of Homogeneous Chitosan-based Composite Scaffolds

    Institute of Scientific and Technical Information of China (English)

    LI Hong; ZHOU Changren; ZHU Minying; TIAN Jinhuan; RONG Jianhua

    2012-01-01

    With a homogeneous distribution of hydroxyapatite (HAP) crystals in polymer matrix,composite scaffolds chitosan/HAP and chitosan/collagen/HAP were fabricated in the study.XRD,SEM and EDX were used to characterize their components and structure,in vitro cell culture and in vivo animal tests were used to evaluate their biocompatibility.HAP crystals with rod-like shape embeded in chitosan scaffold,while HAP fine-granules bond with collagen/chitosan scaffold compactly.A homogenous distribution of Ca and P elements both in chitosan/HAP scaffold and chitosan/collagen/HAP scaffold was defined by EDX pattern.The presence of collagen brought a more homogenous distribution of HAP due to its higher ability to induce HAP precipitation.The results of in vitro cell culture showed that the composite's biocompatibility was enhanced by the homogenous distribution of HAP.In vivo animal studies showed that the in vivo biodegradation was effectively improved by the addition of HAP and collagen,and was less influenced by the homogeneous distribution of HAP when compared with a concentrated distribution one.The composite scaffolds with a homogeneous HAP distribution would be excellent alternative scaffolds for bone tissue engineering.

  14. In vitro corrosion behavior and cytotoxicity property of magnesium matrix composite with chitosan coating

    Institute of Scientific and Technical Information of China (English)

    戴翌龙; 余琨; 陈良建; 陈畅; 乔雪岩; 颜阳

    2015-01-01

    Mg-6%Zn-10%β-Ca3(PO4)2 composite was prepared through powder metallurgy methods with different chitosan coatings on its surface. The properties of the chitosan coatings on the surface of Mg-6%Zn-10%β-Ca3(PO4)2 composite, such as the adhesion ability, the corrosion behavior and the cytotoxicity properties, were investigated, and the microstructure of the chitosan coating was observed by scanning electron microscope (SEM). The results show that chitosan coating improves the corrosion resistance of the magnesium composite specimens significantly. Mg-6%Zn-10%β-Ca3(PO4)2 composite specimens exhibit good corrosion resistance and low pH values in simulated body fluid (SBF) at 37 °C in the immersion test with 7-layer chitosan coating whose relative molecular mass is 30×104 Da. The cytotoxicity tests indicate that Mg-6%Zn-10%β-Ca3(PO4)2 with chitosan coating is nontoxic with a cytotoxicity grade of zero against L-929 cells, which is better than that of uncoated composites.

  15. Effects of chitosan-oil coating on blue mold disease and quality attributes of jujube fruits.

    Science.gov (United States)

    Xing, Yage; Xu, Qinglian; Che, Zhenming; Li, Xihong; Li, Wenting

    2011-08-01

    The effects of chitosan coating enriched with cinnamon oil on blue mold disease and quality attributes were investigated. In the in vitro experiment, the results demonstrated that the antifungal activity against P. citrinum improved with increasing concentration of chitosan or cinnamon oil. In the in vivo study, chitosan-oil treatments significantly reduced fungal decay caused by P. citrinum and all compounds with cinnamon oil at 2.0% showed complete control of the growth of P. citrinum on wound-inoculated fruits. High chitosan-oil concentrations correlated with low disease incidence regardless of storage temperature. Treatments of chitosan-oil coating also inhibited the activity of polyphenol oxidase and maintained vitamin C and phenolic compounds in wounded jujube fruits. Results suggested that the effect of chitosan coating (1.0%) enriched with cinnamon oil (0.75%) on blue mold in jujube fruits may be associated with fungitoxic properties against the pathogen and the elicitation of biochemical defense responses in fruits. PMID:21837310

  16. Fabrication, nanomechanical characterization, and cytocompatibility of gold-reinforced chitosan bio-nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Patel, Nimitt G. [Department of Mechanical and Aeronautical Engineering, Clarkson University, Potsdam, NY, 13699 (United States); Materials Science and Engineering PhD Program, Clarkson University, Potsdam, NY, 13699 (United States); Kumar, Ajeet [Center for Advanced Materials Processing, Clarkson University, Potsdam, NY, 13699 (United States); Jayawardana, Veroni N. [Department of Mathematics, Clarkson University, Potsdam, NY, 13699 (United States); Woodworth, Craig D. [Department of Biology, Clarkson University, Potsdam, NY, 13699 (United States); Yuya, Philip A., E-mail: pyuya@clarkson.edu [Department of Mechanical and Aeronautical Engineering, Clarkson University, Potsdam, NY, 13699 (United States)

    2014-11-01

    Chitosan, a naturally derived polymer represents one of the most technologically important classes of active materials with applications in a variety of industrial and biomedical fields. Gold nanoparticles (∼ 32 nm) were synthesized via a citrate reduction method from chloroauric acid and incorporated in Chitosan matrix. Bio-nanocomposite films with varying concentrations of gold nanoparticles were prepared through solution casting process. Uniform distribution of gold nanoparticles was achieved throughout the chitosan matrix and was confirmed with SEM. Synthesis outcomes and prepared nanocomposites were characterized using SEM, TEM, EDX, SAED, UV–vis, XRD, DLS, and Zeta potential for their physical, morphological and structural properties. Nanoscale properties of materials under the influence of temperature were characterized through nanoindentation techniques. From quasi-static nanoindentation, it was observed that hardness and reduced modulus of the nanocomposites were increased significantly in direct proportion to the gold nanoparticle concentration. Gold nanoparticle concentration also showed positive impact on storage modulus and thermal stability of the material. The obtained films were confirmed to be biocompatible by their ability to support growth of human cells in vitro. In summary, the results show enhanced mechanical properties with increasing gold nanoparticle concentration, and provide better understanding of the structure–property relationships of such biocompatible materials for potential biomedical applications. - Highlights: • We fabricated gold reinforced chitosan nanocomposite for biomedical applications. • Gold nanoparticles significantly enhanced nanomechanical properties of chitosan. • Nanocomposite films supported growth of human cells in vitro. • Gold nanoparticles significantly improved cell proliferation on chitosan films.

  17. Fabrication, nanomechanical characterization, and cytocompatibility of gold-reinforced chitosan bio-nanocomposites

    International Nuclear Information System (INIS)

    Chitosan, a naturally derived polymer represents one of the most technologically important classes of active materials with applications in a variety of industrial and biomedical fields. Gold nanoparticles (∼ 32 nm) were synthesized via a citrate reduction method from chloroauric acid and incorporated in Chitosan matrix. Bio-nanocomposite films with varying concentrations of gold nanoparticles were prepared through solution casting process. Uniform distribution of gold nanoparticles was achieved throughout the chitosan matrix and was confirmed with SEM. Synthesis outcomes and prepared nanocomposites were characterized using SEM, TEM, EDX, SAED, UV–vis, XRD, DLS, and Zeta potential for their physical, morphological and structural properties. Nanoscale properties of materials under the influence of temperature were characterized through nanoindentation techniques. From quasi-static nanoindentation, it was observed that hardness and reduced modulus of the nanocomposites were increased significantly in direct proportion to the gold nanoparticle concentration. Gold nanoparticle concentration also showed positive impact on storage modulus and thermal stability of the material. The obtained films were confirmed to be biocompatible by their ability to support growth of human cells in vitro. In summary, the results show enhanced mechanical properties with increasing gold nanoparticle concentration, and provide better understanding of the structure–property relationships of such biocompatible materials for potential biomedical applications. - Highlights: • We fabricated gold reinforced chitosan nanocomposite for biomedical applications. • Gold nanoparticles significantly enhanced nanomechanical properties of chitosan. • Nanocomposite films supported growth of human cells in vitro. • Gold nanoparticles significantly improved cell proliferation on chitosan films

  18. Chitosan enhances parasitism of Meloidogyne javanica eggs by the nematophagous fungus Pochonia chlamydosporia.

    Science.gov (United States)

    Escudero, Nuria; Ferreira, Sebastião R; Lopez-Moya, Federico; Naranjo-Ortiz, Miguel A; Marin-Ortiz, Ana I; Thornton, Christopher R; Lopez-Llorca, Luis V

    2016-04-01

    Pochonia chlamydosporia (Pc), a nematophagous fungus and root endophyte, uses appressoria and extracellular enzymes, principally proteases, to infect the eggs of plant parasitic nematodes (PPN). Unlike other fungi, Pc is resistant to chitosan, a deacetylated form of chitin, used in agriculture as a biopesticide to control plant pathogens. In the present work, we show that chitosan increases Meloidogyne javanica egg parasitism by P. chlamydosporia. Using antibodies specific to the Pc enzymes VCP1 (a subtilisin), and SCP1 (a serine carboxypeptidase), we demonstrate chitosan elicitation of the fungal proteases during the parasitic process. Chitosan increases VCP1 immuno-labelling in the cell wall of Pc conidia, hyphal tips of germinating spores, and in appressoria on infected M. javanica eggs. These results support the role of proteases in egg parasitism by the fungus and their activation by chitosan. Phylogenetic analysis of the Pc genome reveals a large diversity of subtilisins (S8) and serine carboxypeptidases (S10). The VCP1 group in the S8 tree shows evidence of gene duplication indicating recent adaptations to nutrient sources. Our results demonstrate that chitosan enhances Pc infectivity of nematode eggs through increased proteolytic activities and appressoria formation and might be used to improve the efficacy of M. javanica biocontrol. PMID:27020158

  19. Chitosan use in chemical conditioning for dewatering municipal-activated sludge.

    Science.gov (United States)

    Zemmouri, H; Mameri, N; Lounici, H

    2015-01-01

    This work aims to evaluate the potential use of chitosan as an eco-friendly flocculant in chemical conditioning of municipal-activated sludge. Chitosan effectiveness was compared with synthetic cationic polyelectrolyte Sedipur CF802 (Sed CF802) and ferric chloride (FeCl₃). In this context, raw sludge samples from Beni-Messous wastewater treatment plant (WWTP) were tested. The classic jar test method was used to condition sludge samples. Capillary suction time (CST), specific resistance to filtration (SRF), cakes dry solid content and filtrate turbidity were analyzed to determine filterability, dewatering capacity of conditioned sludge and the optimum dose of each conditioner. Data exhibit that chitosan, FeCl₃and Sed CF802 improve sludge dewatering. Optimum dosages of chitosan, Sed CF802 and FeCl₃allowing CST values of 6, 5 and 9 s, were found, respectively, between 2-3, 1.5-3 and 6 kg/t ds. Both polymers have shown faster water removal with more permeable sludge. SRF values were 0.634 × 10¹², 0.932 × 10¹² and 2 × 10¹² m/kg for Sed CF802, chitosan and FeCl₃respectively. A reduction of 94.68 and 87.85% of the filtrate turbidity was obtained with optimal dosage of chitosan and Sed CF802, respectively. In contrast, 54.18% of turbidity abatement has been obtained using optimal dosage of FeCl₃.

  20. Iron casein succinylate-chitosan coacervate for the liquid oral delivery of iron with bioavailability and stability enhancement.

    Science.gov (United States)

    Min, Kyoung Ah; Cho, Jung-Hye; Song, Yun-Kyoung; Kim, Chong-Kook

    2016-01-01

    Iron casein succinylate (ICS) liquid oral preparation as iron supplement has uncomfortable taste after a long period of storage because of its stability, and poor bioavailability of iron compared to any other iron preparations. To improve the chemical stability of ICS and enhance the bioavailability of iron, chitosan-ICS nanoparticles (NPs) were prepared by complex coacervation method and stabilized with polyethylene glycol (PEG) 400. NPs were spherical (mean diameter of 830-1070 nm) with positive charge (+30-60 mV) depending on the composition of NPs. Addition of PEG400 (2 w/v %) increased the zeta potential (26-50 %) and physical stability of chitosan-ICS NPs suspension. Also, NPs decreased iron release compared to ICS after 7-weeks of storage at 4 °C. NPs markedly increased the permeability of iron in Caco-2 cell up to 32-38-fold compared to ICS, while physical mixture of chitosan and ICS increased the iron permeability only 2.5-fold. In summary, NPs improved the physicochemical stability and enhanced the transport of iron compared to other iron preparations in Caco-2 cell model. Thus, chitosan-ICS coacervate might be a promising candidate as a liquid oral iron delivery system for iron deficiency patients with stability and bioavailability enhancement.

  1. Chitosan Modification and Pharmaceutical/Biomedical Applications

    Directory of Open Access Journals (Sweden)

    Jiali Zhang

    2010-06-01

    Full Text Available Chitosan has received much attention as a functional biopolymer for diverse applications, especially in pharmaceutics and medicine. Our recent efforts focused on the chemical and biological modification of chitosan in order to increase its solubility in aqueous solutions and absorbability in the in vivo system, thus for a better use of chitosan. This review summarizes chitosan modification and its pharmaceutical/biomedical applications based on our achievements as well as the domestic and overseas developments: (1 enzymatic preparation of low molecular weight chitosans/chitooligosaccharides with their hypocholesterolemic and immuno-modulating effects; (2 the effects of chitin, chitosan and their derivatives on blood hemostasis; and (3 synthesis of a non-toxic ion ligand—D-Glucosaminic acid from Oxidation of D-Glucosamine for cancer and diabetes therapy.

  2. Application of Ferriferous Oxide Modified by Chitosan in Gene Delivery

    OpenAIRE

    Yu Kuang; Tun Yuan; Zhongwei Zhang; Mingyuan Li; Yuan Yang

    2012-01-01

    New approaches to improve the traditional gene carriers are still required. Here we explore Fe3O4 modified with degradable polymers that enhances gene delivery and target delivery using permanent magnetic field. Two magnetic Fe3O4 nanoparticles coated with chitosan (CTS) and polyethylene glycol (PEG) were synthesized by means of controlled chemical coprecipitation. Plasmid pEGFP was encapsulated as a reported gene. The ferriferous oxide complexes were approximately spherical; surface charge o...

  3. Innovative Composite Films of Chitosan, Methylcellulose, and Nanoparticles

    OpenAIRE

    Mura, Stefania; Corrias, Francesco; Stara, Giuseppe; Piccinini, Massimo; Secchi, Nicola; Marongiu, Daniela; Innocenzi, Plinio; Irudayaraj, Joseph; Greppi, Gian F.

    2011-01-01

    Plastic is readily available and inexpensive, so it is becoming the main material for packaging. Unfortunately plastics do not biodegrade and, if reduced in small pieces, contaminate soil and waterways. In the present work, natural films composed of chitosan, methylcellulose, and silica (SiO(2)) nanoparticles (NPs) were developed as new packaging materials. The effect of the incorporation of NPs into the polymeric film matrix was evaluated. An excellent improvement of the mechanical propertie...

  4. Preparation and characterization of crosslinked chitosan-based nanofibers

    Institute of Scientific and Technical Information of China (English)

    Ying Shan Zhou; Dong Zhi Yang; Jun Nie

    2007-01-01

    Crosslinked chitosan-based nanofibers were successfully prepared via electrospinning technique with heat mediated chemical crosslinking followed. The structure, morphology and mechanical property of nanofibers were characterized by attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR), scanning electron microscopy (SEM), Instron machine, respectively. The results showed that, nanofibers exhibited a smooth surface and regular morphology, and tensile strength of nanofibers improved with increasing of triethylene glycol dimethacrylate (TEGDMA) content.

  5. Covalently Bonded Chitosan on Graphene Oxide via Redox Reaction

    OpenAIRE

    Castaño, Víctor M; Carlos Velasco-Santos; Miguel de Icaza; Gonzalo Martínez-Barrera; Karina Bustos-Ramírez; Ana L. Martínez-Hernández

    2013-01-01

    Carbon nanostructures have played an important role in creating a new field of materials based on carbon. Chemical modification of carbon nanostructures through grafting has been a successful step to improve dispersion and compatibility in solvents, with biomolecules and polymers to form nanocomposites. In this sense carbohydrates such as chitosan are extremely valuable because their functional groups play an important role in diversifying the applications of carbon nanomaterials. This paper ...

  6. In Vitro Degradation of Polyglycolide/Chitosan Hybrid Braids

    Institute of Scientific and Technical Information of China (English)

    YUAN Xiaoyan; ZHANG Qingwei; WANG Yonglin; YAO Kangde

    2005-01-01

    Hybrid braids of polyglycolide (PGA) and chitosan were prepared by the three-yarn braiding method from PGA and chitosan fiber bundles. These braids were in vitro degraded by incubating them in phosphate buffered saline (PBS) at pH 7.4 and 37 ℃ for 5 weeks. Results suggested that PGA/chitosan hybrid braids degraded significantly. Scanning electron micrographs showed that chitosan fibers in the PGA/chitosan hybrid braid with about 750% PGA in weight (PGA75/chitosan) were shaped into gel-like after 5 weeks, but those in the hybrid braid with about 250% PGA in weight (PGA25/chitosan) did not change. After 5 weeks, the ultimate tensile loads of PGA and PGA75/chitosan braids lost almost completely, but those of chitosan and PGA25/chitosan braids remained around 14 N. The PGA/chitosan hybrid braids with higher initial ultimate tensile load would have potential applications in tendon/ligament tissue reconstruction.

  7. Synthesis, characterization and radiation processing of carboxymethyl-chitosan

    International Nuclear Information System (INIS)

    Chitosan is natural polymer derived from chitin, a polysaccharide found in the exoskeleton of shrimps, crabs, fungi and others. Chitosan is a naturally occurring substance that is chemically similar to cellulose. Chitosan possesses a positive ionic charge give ability to chemically bond with negatively charged fats. Chitosan is soluble in organic acid but insoluble in water. Carboxymethyl-chitosan (cm-chitosan) is a derivative of chitosan which is water-soluble was then prepared by carboxymethylation process of chitosan produced from local shrimp shell. A simple method for synthesis of cm-chitosan has been developed at 55 degree C in aqueous sodium hydroxide / propanol with chloroacetic acid (CAA) or sodium chloroacetate salt (SCA). The modification of chitosan to water-soluble chitosan can be used in hydrogel as anti-bacterial and anti-fungal agent, and it overcome the problem of bad smell using organic acid. (Author)

  8. Radiation processing of chitosan derivative and its characteristics

    International Nuclear Information System (INIS)

    Chitosan is natural polymer derived from chitin, a polysaccharide found in the exoskeleton of shrimps, crabs, fungi and others. Chitosan is a naturally occurring substance that is chemically similar to cellulose. Chitosan possesses a positive ionic charge give ability to chemically bond with negatively charged fats. Chitosan is soluble in organic acid but insoluble in water. Carboxymethyl-chitosan (cm-chitosan) is a derivative of chitosan which is water-soluble was then prepared by a carboxymethylation process of chitosan produced from local shrimp shell. A simple method for synthesis of cm-chitosan has been developed at 55 degree C in aqueous sodium hydroxide / propanol with chloroacetic acid (CAA) or sodium chloroacetate salt (SCA). The modification of chitosan to water-soluble chitosan can be used in hydrogel as anti-bacterial agent and it overcome the problem of bad smell using acetic acid. (Author)

  9. ADSORPTION OF LDL ON THE MODIFIED CHITOSAN

    Institute of Scientific and Technical Information of China (English)

    LIUManying; ZHAOLirui; 等

    2000-01-01

    In this paper,the selective adsorption of LDL on chitosan modified with PEG and Asp.was studied.The adsorption rate of LDL and HDL on the double modified chitosan was 57% and 12% respoectively,The results shown that the double modified chitosan can be used a adsorbent for selective binding to LDL,this work may help to develop functional columns for hemoperfusion.

  10. Breeding of maize types with specific traits at the Maize Research Institute, Zemun Polje

    Directory of Open Access Journals (Sweden)

    Pajić Zorica

    2007-01-01

    Full Text Available Maize is primarily grown as an energy crop, but the use of different specific versions, such as high-oil maize, high-lysine maize, waxy maize, white-seeded maize, popping maize and sweet maize, is quite extensive. Speciality maize, due to its traits and genetic control of these traits, requires a particular attention in handling breeding material during the processes of breeding. It is especially related to prevention of uncontrolled pollination. In order to provide successful selection for a certain trait, the following specific procedures in evaluation of the trait are necessary: the estimation of a popping volume and flake quality in popping maize; the determination of sugars and harvest maturity in sweet maize; the determination of oil in selected samples of high-oil maize types, and so forth. Breeding programmes for speciality maize, except high-amylose maize, have been implemented at the Maize Research Institute, Zemun Polje, Belgrade, for the last 45 years. A great number of high-yielding sweet maize hybrids, popping maize, high-oil and high-lysine, flint and white-seeded maize hybrids were developed during this 45-year period. Auspicious selection and breeding for these traits is facilitated by the abundant genetic variability and technical and technological possibilities necessary for successful selection.

  11. Specific optical rotation indicatrices of chitosan films

    Science.gov (United States)

    Rudenko, Darya A.; Shipovskaya, Anna B.

    2016-04-01

    The optical activity of chitosan films in the forms of polysalt (chitosan acetate) and polybase was studied. The specific optical rotation [α] of all our films was negative. The absolute values of [α] of polybasic chitosan films was by an order of magnitude higher than that for polysalt films. A dependence of [α] on the orientation angle of the sample relative to the direction of the polarization vector of the incident light beam in the plane perpendicular to this beam was established. Specific optical rotation indicatrices of the chitosan films of both chemical forms were plotted.

  12. Agrobacterium-mediated transformation of maize (Zea mays) immature embryos.

    Science.gov (United States)

    Lee, Hyeyoung; Zhang, Zhanyuan J

    2014-01-01

    Agrobacterium tumefaciens-mediated transformation is one of the most efficient and simple gene delivery systems for genetic improvement and biology studies in maize. This system has become more widely used by both public and private laboratories. However, transformation efficiencies vary greatly from laboratory to laboratory for the same genotype. Here, we illustrate our advanced Agrobacterium-mediated transformation method in Hi-II maize using simple binary vectors. The protocol utilizes immature embryos as starting explants and the bar gene as a selectable marker coupled with bialaphos as a selective agent. The protocol offers efficient transformation results with high reproducibility, provided that some experimental conditions are well controlled. This transformation method, with minor modifications, can be also employed to transform certain maize inbreds.

  13. Characterization of Chitosan and fabrication of Chitosan hydrogels matrices for biomedical applications

    Directory of Open Access Journals (Sweden)

    Charhouf I.

    2013-09-01

    Full Text Available The development of injectable hydrogels for drug delivery is a major challenge. Chitosan is a copolymer of N-acetylglucosamine and glucosamine units and is represented as a copolymer. Chitosan occurs in nature in the cell walls of some fungi, exoskeletons of insects and marine animals such as crabs and prawns. Chitosan and its derivatives possess a wide range of useful properties. They are biodegradable, and biocompatible with antibacterial and antioxidant activities. They are useful in drug delivery formulations and tissue engineering. The objective of the present study was to characterize chitosan, prepare chitosan hydrogels and study the gelation of this hydrogels over time. Chitosan with DDA% ∼ 80%–90% were characterized by infrared spectroscopy, conductimetry and pH-metry. In addition, chitosan hydrogels were prepared using an ionic gelation method making it suitable for biomedical applications.

  14. Fish gelatin combined with chitosan coating inhibits myofibril degradation of golden pomfret (Trachinotus blochii) fillet during cold storage.

    Science.gov (United States)

    Feng, Xiao; Bansal, Nidhi; Yang, Hongshun

    2016-06-01

    Coating of gelatin and chitosan can improve fish fillet's quality, but the mechanism is not clear. Chitosan/gelatin coatings significantly prevented deterioration of golden pomfret fillet at 4 °C. Chitosan with 7.2% gelatin group showed the best effect on preserving the length of myofibril, which remained greater than 15 μm at day 17 of storage, while for control, chitosan and chitosan combined with 3.6% gelatin group, it was 5.03, 10.04 and 9.02 μm, respectively. The MALDI-TOF MS result revealed that the coatings slowed down the protein deterioration of fillet. On days 13 and 17, the myosin light chain and myoglobin in control group degraded, while the two proteins still existed in chitosan/gelatin coated groups. Overall, the chitosan with 7.2% gelatin coating had the best effect on preserving fillet's quality during storage. The coating may exert its protective effect via inhibiting myofibril degradation within fillet. PMID:26830590

  15. Controllable degradation of medical magnesium by electrodeposited composite films of mussel adhesive protein (Mefp-1) and chitosan.

    Science.gov (United States)

    Jiang, Ping-Li; Hou, Rui-Qing; Chen, Cheng-Dong; Sun, Lan; Dong, Shi-Gang; Pan, Jin-Shan; Lin, Chang-Jian

    2016-09-15

    To control the degradation rate of medical magnesium in body fluid environment, biocompatible films composed of Mussel Adhesive Protein (Mefp-1) and chitosan were electrodeposited on magnesium surface in cathodic constant current mode. The compositions and structures of the films were characterized by atomic force microscope (AFM), scanning electron microscope (SEM) and infrared reflection absorption spectroscopy (IRAS). And the corrosion protection performance was investigated using electrochemical measurements and immersion tests in simulated body fluid (Hanks' solution). The results revealed that Mefp-1 and chitosan successfully adhered on the magnesium surface and formed a protective film. Compared with either single Mefp-1 or single chitosan film, the composite film of chitosan/Mefp-1/chitosan (CPC (chitosan/Mefp-1/chitosan)) exhibited lower corrosion current density, higher polarization resistance and more homogenous corrosion morphology and thus was able to effectively control the degradation rate of magnesium in simulated body environment. In addition, the active attachment and spreading of MC3T3-E1 cells on the CPC film coated magnesium indicated that the CPC film was significantly able to improve the biocompatibility of the medical magnesium. PMID:27309944

  16. Nitrogen/Sulfur-Codoped Carbon Materials from Chitosan for Supercapacitors

    Science.gov (United States)

    Li, Mei; Han, Xianlong; Chang, Xiaoqing; Yin, Wenchao; Ma, Jingyun

    2016-08-01

    d-Methionine and chitosan have been used for fabrication of nitrogen/sulfur-codoped carbon materials by a hydrothermal process followed by carbonization at 750°C for 3 h. The as-prepared carbon materials showed enhanced electrochemical performance, combining electrical double-layer capacitance with pseudocapacitance owing to the doping with sulfur and nitrogen. The specific capacitance of the obtained carbon material reached 135 F g-1 at current density of 1 A g-1, which is much higher than undoped chitosan (67 F g-1). The capacitance retention of the carbon material was almost 97.2% after 5000 cycles at current density of 1 A g-1. With such improved electrochemical performance, the nitrogen/sulfur-codoped carbon material may have promising potential for use in energy-storage electrodes of supercapacitors.

  17. Photonic monitoring of chitosan nanostructured alginate microcapsules for drug release

    Science.gov (United States)

    Khajuria, Deepak Kumar; Konnur, Manish C.; Vasireddi, Ramakrishna; Roy Mahapatra, D.

    2015-02-01

    By using a novel microfluidic set-up for drug screening applications, this study examines delivery of a novel risedronate based drug formulation for treatment of osteoporosis that was developed to overcome the usual shortcomings of risedronate, such as its low bioavailability and adverse gastric effects. Risedronate nanoparticles were prepared using muco-adhesive polymers such as chitosan as matrix for improving the intestinal cellular absorption of risedronate and also using a gastric-resistant polymer such as sodium alginate for reducing the gastric inflammation of risedronate. The in-vitro characteristics of the alginate encapsulated chitosan nanoparticles are investigated, including their stability, muco-adhesiveness, and Caco-2 cell permeability. Fluorescent markers are tagged with the polymers and their morphology within the microcapsules is imaged at various stages of drug release.

  18. Preparation and antibacterial activity of quaternized chitosan with iodine

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Yang; Xie, Linlin; Sai, Mingze; Xu, Ningning; Ding, Derun, E-mail: dingderun@sues.edu.cn

    2015-03-01

    Chitosan (CTS) is a natural polymer with active groups such as –NH{sub 2} which can be functionalized to introduce new positively charged N-atoms and protonated amino group for better use. In this study, to improve the stability of iodine, a novel complex (CTS–CTA–I{sub 2}) was prepared by mixing N-(2-hydroxy) propyl-3-trimethylammonium chitosan chloride (CTS–CTA) with iodine in ethanol solution. The CTS–CTA–I{sub 2} was characterized by Fourier transform infrared spectra (FTIR), Ultraviolet and visible (UV–vis) spectra and thermal gravimetric analysis (TG). Besides, the interaction of iodine with CTS–CTA was also studied. The mole ratio of CTS–CTA with iodine was measured by iodometric titration method and the max mole ratio of CTS–CTA with iodine was 1:1.33. The antimicrobial activity of CTS, CTS–CTA and CTS–CTS–I{sub 2} complexes was investigated against Escherichia coli and Staphylococcus aureus and the antibacterial property of CTS–CTA–I{sub 2} was superior to CTS–CTA. - Highlights: • We prepared a novel iodine complex based on chitosan. • The CTS–CTA–I{sub 2} complex improved the stability of iodine. • The max mole ratio of CTS–CTA with iodine was 1:1.33. • The CTS–CTA–I{sub 2} complex showed significant antibacterial activity.

  19. Oxidized Xanthan Gum and Chitosan as Natural Adhesives for Cork

    Directory of Open Access Journals (Sweden)

    Diana Paiva

    2016-07-01

    Full Text Available Natural cork stopper manufacturing produces a significant amount of cork waste, which is granulated and combined with synthetic glues for use in a wide range of applications. There is a high demand for using biosourced polymers in these composite materials. In this study, xanthan gum (XG and chitosan (CS were investigated as possible natural binders for cork. Xanthan gum was oxidized at two different aldehyde contents as a strategy to improve its water resistance. This modification was studied in detail by 1H and 13C nuclear magnetic resonance (NMR, and the degree of oxidation was determined by the hydroxylamine hydrochloride titration method. The performance of the adhesives was studied by tensile tests and total soluble matter (TSM determinations. Xanthan gum showed no water resistance, contrary to oxidized xanthan gum and chitosan. It is hypothesized that the good performance of oxidized xanthan gum is due to the reaction of aldehyde groups—formed in the oxidation process—with hydroxyl groups on the cork surface during the high temperature drying. Combining oxidized xanthan gum with chitosan did not yield significant improvements.

  20. Chitosan-Iron Oxide Coated Graphene Oxide Nanocomposite Hydrogel: A Robust and Soft Antimicrobial Biofilm.

    Science.gov (United States)

    Konwar, Achyut; Kalita, Sanjeeb; Kotoky, Jibon; Chowdhury, Devasish

    2016-08-17

    We report a robust biofilm with antimicrobial properties fabricated from chitosan-iron oxide coated graphene oxide nanocomposite hydrogel. For the first time, the coprecipitation method was used for the successful synthesis of iron oxide coated graphene oxide (GIO) nanomaterial. After this, films were fabricated by the gel-casting technique aided by the self-healing ability of the chitosan hydrogel network system. Both the nanomaterial and the nanocomposite films were characterized by techniques such as scanning electron microscopy, FT-IR spectroscopy, X-ray diffraction, and vibrating sample magnetometry. Measurements of the thermodynamic stability and mechanical properties of the films indictaed a significant improvement in their thermal and mechanical properties. Moreover, the stress-strain profile indicated the tough nature of the nanocomposite hydrogel films. These improvements, therefore, indicated an effective interaction and good compatibility of the GIO nanomaterial with the chitosan hydrogel matrix. In addition, it was also possible to fabricate films with tunable surface properties such as hydrophobicity simply by varying the loading percentage of GIO nanomaterial in the hydrogel matrix. Fascinatingly, the chitosan-iron oxide coated graphene oxide nanocomposite hydrogel films displayed significant antimicrobial activities against both Gram-positive and Gram-negative bacterial strains, such as methicillin-resistant Staphylococcus aureus, Staphylococcus aureus, and Escherichia coli, and also against the opportunistic dermatophyte Candida albicans. The antimicrobial activities of the films were tested by agar diffusion assay and antimicrobial testing based on direct contact. A comparison of the antimicrobial activity of the chitosan-GIO nanocomposite hydrogel films with those of individual chitosan-graphene oxide and chitosan-iron oxide nanocomposite films demonstrated a higher antimicrobial activity for the former in both types of tests. In vitro hemolysis

  1. Cell Compound of Wound Surface After the Chitosan Membranes Application

    Directory of Open Access Journals (Sweden)

    Alexandr N. Oleshko

    2014-12-01

    Full Text Available Skin regeneration is a complex dynamic process by which restores the structure and function of the external cover. In the case of large defects of the skin allografts were the methods of choice in recent decades. The disadvantages of this therapy are the presence of pain, the appearance of scars and increased mortality. The tissue engineering methods artificial materials are widely developed in recent decades for large skin defects treatment. Chitosan is one of the most promising agents in the development of materials for the treatment of major defects of the skin. Currently, there are materials in the form of hydrogel, membranes and sponges based on chitosan, which has shown high efficacy in the treatment of wounds, both in experimental and clinical settings. Nevertheless, there is a need to find new forms and compositions based on chitosan to improve health outcomes, reduce product cost and optimizing the production of materials. The aim of this work was to study the features of skin regeneration after mechanical trauma when applying chitosan membranes at the different ages. The study of the processes of skin regeneration was carried out on 180 white laboratory rats of three age categories. All the animals were randomized into 2 series - experimental and control. After injury, the animals of control series were performed daily standard wound toilet with sterile gauze, experimental series - for the topical treatment received daily applications of experimental chitosan membranes. The animals were taken from the experiment in 1, 3, 7, 14 and 21 days, which corresponds to the terms that characterize the main stages of the process of skin regeneration. We used scraping by "surface biopsy" method as well as skin imprint to get a full picture of the cellular composition of the surface defect. The use of chitosan films in the management of mechanical trauma to the skin helps to optimize intercellular cooperation, reduce the severity of inflammatory

  2. Genetic relationships and structure among open pollinated maize varieties adapted to eastern and southern Africa using microsatellite markers

    Science.gov (United States)

    The International Maize and Wheat Improvement Center (CIMMYT), in collaboration with the national agricultural systems (NARS) in sub-Saharan Africa (SSA), have developed various stress-tolerant and more nutritious open-pollinated varieties (OPVs) of maize that are suitable for smallholder farmers’ g...

  3. Bioavailability of iron, zinc, folic acid, and vitamin A from fortified maize.

    Science.gov (United States)

    Moretti, Diego; Biebinger, Ralf; Bruins, Maaike J; Hoeft, Birgit; Kraemer, Klaus

    2014-04-01

    Several strategies appear suitable to improve iron and zinc bioavailability from fortified maize, and fortification per se will increase the intake of bioavailable iron and zinc. Corn masa flour or whole maize should be fortified with sodium iron ethylenediaminetetraacetate (NaFeEDTA), ferrous fumarate, or ferrous sulfate, and degermed corn flour should be fortified with ferrous sulfate or ferrous fumarate. The choice of zinc fortificant appears to have a limited impact on zinc bioavailability. Phytic acid is a major inhibitor of both iron and zinc absorption. Degermination at the mill will reduce phytic acid content, and degermed maize appears to be a suitable vehicle for iron and zinc fortification. Enzymatic phytate degradation may be a suitable home-based technique to enhance the bioavailability of iron and zinc from fortified maize. Bioavailability experiments with low phytic acid-containing maize varieties have suggested an improved zinc bioavailability compared to wild-type counterparts. The bioavailability of folic acid from maize porridge was reported to be slightly higher than from baked wheat bread. The bioavailability of vitamin A provided as encapsulated retinyl esters is generally high and is typically not strongly influenced by the food matrix, but has not been fully investigated in maize.

  4. Degradation of chitosan for rice crops application

    International Nuclear Information System (INIS)

    A variety of techniques including chemical and enzymatic hydrolysis, and radiation degradation processes can be used to prepare low molecular weight chitosan. Degradation of chitosan by radiation can be carried out in solid state and liquid state. Radiation degraded polysaccharides has been reported to exhibit growth-stimulating activity like phytohormones that induce the promotion in germination, shoot and root elongation in variety of plants. In this study, the chitosan was irradiated in solid state (powder form) by gamma rays within the dose range of 25-75 kGy. And the irradiated chitosan was then irradiated in solution form in the presence of hydrogen peroxide. The effects of irradiation on the molecular weight and viscosity of the chitosan were investigated using Ubbelohde Capillary Viscometer. The molecular weight and viscosity of the chitosan decreased with increment of absorbed doses. In the presence of hydrogen peroxide, the molecular weight of chitosan could be further decreased. The effect of radiation degraded chitosan on the growth promotion of rice was investigated and it was shown during seedling period of 15 days for transplanting whereby the growth is 15%-20% faster than using chemicals growth promoters. (authors)

  5. Application of irradiated chitosan for fruit preservation

    International Nuclear Information System (INIS)

    Application of irradiated chitosan has been investigated for coating of fruit preservation. Anti-fungal activity of chitosan was induced by γ-ray irradiation in dry condition at 25 kGy. The irradiated chitosan can suppress the growth of Aspergillus. spp. and Fusarium. spp. isolated from Vietnam mango. Fusarium. spp. was sensitive for irradiated chitosan than the other strains. The coating from irradiated chitosan solution at dose 31 kGy has prolonged the storage life of mango from 7 to 15 days. At the 15th day mango keeps good colour, natural ripening, without spoilage, weight loss 10%, whereas the control is spoiled completely and the sample of fruit with unirradiated chitosan coating could not ripe. The effect is due to the anti-fungal activity and change in physico-chemical properties of chitosan by irradiation. Radiation causes the decrease in viscosity affecting the gas permeability of coating film. The irradiated chitosan coating has positive effect on mango that is susceptible to chilling injury at low storage temperature. (author)

  6. Inbreeding drives maize centromere evolution.

    Science.gov (United States)

    Schneider, Kevin L; Xie, Zidian; Wolfgruber, Thomas K; Presting, Gernot G

    2016-02-23

    Functional centromeres, the chromosomal sites of spindle attachment during cell division, are marked epigenetically by the centromere-specific histone H3 variant cenH3 and typically contain long stretches of centromere-specific tandem DNA repeats (∼1.8 Mb in maize). In 23 inbreds of domesticated maize chosen to represent the genetic diversity of maize germplasm, partial or nearly complete loss of the tandem DNA repeat CentC precedes 57 independent cenH3 relocation events that result in neocentromere formation. Chromosomal regions with newly acquired cenH3 are colonized by the centromere-specific retrotransposon CR2 at a rate that would result in centromere-sized CR2 clusters in 20,000-95,000 y. Three lines of evidence indicate that CentC loss is linked to inbreeding, including (i) CEN10 of temperate lineages, presumed to have experienced a genetic bottleneck, contain less CentC than their tropical relatives; (ii) strong selection for centromere-linked genes in domesticated maize reduced diversity at seven of the ten maize centromeres to only one or two postdomestication haplotypes; and (iii) the centromere with the largest number of haplotypes in domesticated maize (CEN7) has the highest CentC levels in nearly all domesticated lines. Rare recombinations introduced one (CEN2) or more (CEN5) alternate CEN haplotypes while retaining a single haplotype at domestication loci linked to these centromeres. Taken together, this evidence strongly suggests that inbreeding, favored by postdomestication selection for centromere-linked genes affecting key domestication or agricultural traits, drives replacement of the tandem centromere repeats in maize and other crop plants. Similar forces may act during speciation in natural systems. PMID:26858403

  7. Preparation and Blood Compatibility of Oxidized-chitosan Films

    Institute of Scientific and Technical Information of China (English)

    Yue Dong YANG; Jiu Gao YU; Yong Guo ZHOU; Pei Guo LI

    2005-01-01

    Chitosan membrane was modified by the selective oxidization of chitosan molecules on its surface with NO2 gas. FTIR spectra indicated there were plenty of-COOH and -COO- groups on the modified membrane surface. The SEM study showed the modified membrane surface was rough rather than smooth as chitosan membrane. All antithrombosis test, hemolysis test and blood cell morphology observation with SEM revealed that modified chitosan membranes have superior blood compatibility to chitosan.

  8. Chitosan Fibers Modified with HAp/beta-TCP Nanoparticles

    OpenAIRE

    Dariusz Wawro; Luciano Pighinelli

    2011-01-01

    This paper describes a method for preparing chitosan fibers modified with hydroxyapatite (HAp), tricalcium phosphate (β-TCP), and HAp/β-TCP nanoparticles. Fiber-grade chitosan derived from the northern shrimp (Pandalus borealis) and nanoparticles of tricalcium phosphate (β-TCP) and hydroxyapatite (HAp) suspended in a diluted chitosan solution were used in the investigation. Diluted chitosan solution containing nanoparticles of Hap/β-TCP was introduced to a 5.16 wt% solution of chitosan in 3.0...

  9. PHARAMACEUTICAL RELEVANCE OF CROSSLINKED CHITOSAN IN MICROPARTICULATE DRUG DELIVERY

    OpenAIRE

    Pahuja Sonia; Aggarwal Shweta

    2013-01-01

    This review highlights the importance of cross-linking with chitosan. Derivatisation of chitosan leads to the cross-linking of chitosan without changing its fundamental skelton structure. Cross-linking agents are broadly divided into two categories i.e Physical and chemical cross-linking; on the basis of interaction with chitosan. The various cross-linking agents used for the preparation of chitosan microspheres and its mechanism of cross-linking have also been described. This article also re...

  10. Preparation and characterization of magnetic chitosan particles for hyperthermia application

    International Nuclear Information System (INIS)

    The size and shape of magnetic chitosan particles were found to be dependent on both the barium ferrite/chitosan (BF/C) ratio and viscosity of a chitosan solution. The saturation magnetization of magnetic chitosan particles varied directly with the BF/C ratio, while coercivity remained almost constant. Notably, incorporated chitosan was shown to exert substantial activity with regard to low cytotoxicity and high heating rate

  11. Faster chitosan production by mucoralean strains in submerged culture

    OpenAIRE

    Amorim Rosa Valéria da Silva; Souza Wanderley de; Fukushima Kazutaka; Campos-Takaki Galba Maria de

    2001-01-01

    Production of chitosan was conducted using two Mucoralean strains, Mucor racemosus and Cunninghamella elegans. Chitosan was extracted from mycelia of M. racemosus and C. elegans at different growth phases on YPD medium. In both fungi, chitosan was rapidly produced, while highest yield of extractable chitosan was found in 24h of cultivation in submerged culture. The yield of chitosan isolated from dry mycelia of M. racemosus was about 40% higher than from C. elegans. The degree of N-acetylatio...

  12. Real-time monitoring of peptide grafting onto chitosan films using capillary electrophoresis.

    Science.gov (United States)

    Taylor, Danielle L; Thevarajah, Joel J; Narayan, Diksha K; Murphy, Patricia; Mangala, Melissa M; Lim, Seakcheng; Wuhrer, Richard; Lefay, Catherine; O'Connor, Michael D; Gaborieau, Marianne; Castignolles, Patrice

    2015-03-01

    Chitosan, being antimicrobial and biocompatible, is attractive as a cell growth substrate. To improve cell attachment, arginine-glycine-aspartic acid-serine (RGDS) peptides were covalently grafted to chitosan films, through the widely used coupling agents 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC-HCl) and N-hydroxysuccinimide (NHS), via the carboxylic acid function of the RGDS molecule. The grafting reaction was monitored, for the first time, in real time using free-solution capillary electrophoresis (CE). This enabled fast separation and determination of the peptide and all other reactants in one separation with no sample preparation. Covalent RGDS peptide grafting onto the chitosan film surface was demonstrated using solid-state NMR of swollen films. CE indicated that oligomers of RGDS, not simply RGDS, were grafted on the film, with a likely hyperbranched structure. To assess the functional properties of the grafted films, cell growth was compared on control and peptide-grafted chitosan films. Light microscopy and polymerase chain reaction (PCR) analysis demonstrated greatly improved cell attachment to RGDS-grafted chitosan films. PMID:25680633

  13. pH and electrical actuation of single walled carbon nanotube/chitosan composite fibers

    Science.gov (United States)

    Ozarkar, Sukrut; Jassal, Manjeet; Agrawal, Ashwini K.

    2008-10-01

    In the present study, an attempt has been made to utilize the pH responsive nature of chitosan to produce fibers which can respond to an applied electric voltage. Single walled carbon nanotubes (SWCNTs) have been used for reinforcing the chitosan fibers. But the SWCNTs are associated with their own challenges of aggregation which have been solved in this study by suitable functionalization. Electron microscopy and Raman spectroscopy was used to investigate the dispersions. The functionalized SWCNTs showed improved dispersion in chitosan. The SWCNT/chitosan composite fibers were successfully solution spun and heat-set to give stable fibers of 50 ± 2 µm. The composite fibers exhibited a significant increase in the mechanical properties. The tenacity of the composite fibers reinforced with functionalized SWCNTs increased from 96 to 226 MPa with an increase in SWCNT content from 0 to 0.2 wt%. The strong interaction of carboxylic functional groups of functionalized SWCNTs with the chitosan matrix may be responsible for the improved dispersion and considerable enhancement of the mechanical properties. Further, the stability of the fibers towards the pH switching environment has also been investigated, along with the response to an applied electric voltage. Composite fibers prepared using 0.1 wt% of functionalized carbon nanotubes were observed to exhibit a stable response with high magnitude of strain and high strain rate.

  14. Preparation and Adsorption Ability of Polysulfone Microcapsules Containing Modified Chitosan Gel

    Institute of Scientific and Technical Information of China (English)

    CHEN Fei; LUO Guangsheng; YANG Weiwei; WANG Yujun

    2005-01-01

    Chemically modified chitosan beads containing polyethyleneimine (PEI) were prepared to improve the metal ion adsorption capacity of the chitosan beads and their mechanical stability and to limit their biodegradability. The modified beads were encapsulated with the polymer material polysulfone by a novel surface coating method named the emulsion phase inversion method. The adsorption properties of the modified beads and the microstructures of the polysulfone coating layer were then analyzed. The experimental results showed that the PEI was successfully linked onto the chitosan beads. The density of the -NH2 groups in the modified beads was significantly increased, while the water content was reduced. The coating layer thickness was about 200 (m. The modified chitosan gel beads had excellent Cu(II) adsorption capacity, with a maximum Cu(II) adsorption capacity 1.34 times higher than that of the unmodified beads. The results show that even with the polysulfone coating the adsorption kinetics of the modified beads is still better than those of the unmodified beads. The modifications improve the mass transfer performance of the chitosan beads as well as the bead stability.

  15. Mechanical and biological properties of chitosan/carbon nanotube nanocomposite films.

    Science.gov (United States)

    Aryaei, Ashkan; Jayatissa, Ahalapitiya H; Jayasuriya, Ambalangodage C

    2014-08-01

    In this article, different concentrations of multiwalled carbon nanotube (MWCNT) were homogeneously dispersed throughout the chitosan (CS) matrix. A simple solvent-cast method was used to fabricate chitosan films with 0.1, 0.5, and 1% of MWCNT with the average diameter around 30 nm. The CS/MWCNT films were characterized for structural, viscous and mechanical properties with optical microscopy, wide-angle X-ray diffraction, Raman spectroscopy, tensile test machine, and microindentation testing machine. Murine osteoblasts were used to examine the cell viability and attachment of the nanocomposite films at two time points. In comparison to the pure chitosan film, the mechanical properties, including the tensile modulus and strength of the films, were greatly improved by increasing the percentage of MWCNT. Furthermore, adding MWCNT up to 1% increased the viscosity of the chitosan solution by 15%. However, adding MWCNT decreased the samples ductility and transparency. In biological point of view, no toxic effect on osteoblasts was observed in the presence of different percentages of MWCNT at day 3 and day 7. This investigation suggested MWCNT could be a promising candidate for improving chitosan mechanical properties without inducing remarkable cytotoxicity on bone cells. PMID:24108584

  16. [Adsorption behaviors of protonation modified chitosan and the analysis of spectra].

    Science.gov (United States)

    Guo, Ying-Juan; Xue, Juan-Qin; Zhang, Jie; Ma, Jing; Quan, Xue-Ting; Liu, Yao

    2014-01-01

    In order to improve adsorbing performance and stability of chitosan in acid simultaneously, cross-linking was employed after the protection of amino groups for improving its stability, then the protection of amino groups was removed and protonated to obtain high adsorption performance. With formaldehyde as amino-group protective agent and glutaraldehyde as cross-linking reagent, cross-linked chitosan (CCTS) was prepared by reversed phase suspension method in this paper, then it was protonated to make protonation modified chitosan adsorbent (P-CCTS). The adsorption performance of sulfate ion onto P-CCTS was firstly studied and investigated by static adsorption test. Elemental analysis by energy dispersive spectrometer of X-rays (EDS) and identifying of functional groups by Fourier transform infrared spectroscopy (FTIR) were used to analyze the preparation and adsorption of the adsorbent, and the reaction mechanism of cross-linking and adsorption was investigated. The results show that the adsorption performance of P-CCTS towards sulfate ion is 10 times higher than that of unmodified chitosan, and formaldehyde and glutaraldehyde mainly react with amino (-NH2) and part of hydroxy (C6-OH) of chitosn. A salt of chitosan protonated amino chlorine was formed through the process of the protonation of amino, the adsorption of sulfate ion mainly occurs on the protonated amino on which ion exchange happened between chlorine ion and sulfate ion.

  17. Chitosan dan Aplikasi Klinisnya Sebagai Biomaterial

    Directory of Open Access Journals (Sweden)

    Bambang Irawan

    2015-10-01

    Full Text Available The development of new materials with both organic and inorganic structures is of great interest to obtain special material properties. Chitosan [2-amino-2-deoxy-D-glucan] can be obtained by N-deacetylation of chitin. Chitin is the second most abundant biopolymer in nature and the supporting material of crustaceans, insects, fungi etc. Chitosan is unique polysaccharide and has been widely used in various biomedical application due to its biocompatibility, low toxicity, biodegradability, non-immunogenic and non-carcinogenic character. In the past few years, chitosan and some of its modifications have been reported for use in biomedical applications such as artificial skin, wound dressing, anticoagulant, suture, drug delivery, vaccine carrier and dietary fibers. Recently, the use of chitosan and its derivatives has received much attention as temporary scaffolding to promotie mineralization or stimulate endochodral ossification. This article aims to give a broad overview of chitosan and its clinical applications as biomaterial.

  18. Preparation and characterization of bio-based hybrid film containing chitosan and silver nanowires.

    Science.gov (United States)

    Shahzadi, Kiran; Wu, Lin; Ge, Xuesong; Zhao, Fuhua; Li, Hui; Pang, Shuping; Jiang, Yijun; Guan, Jing; Mu, Xindong

    2016-02-10

    A bio-based hybrid film containing chitosan (CS) and silver nanowires (AgNWs) has been prepared by a simple casting technique. X-ray diffraction (XRD), Fourier infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and UV-visible spectroscopy were employed to characterize the structure of bio-based film. The bio-based hybrid film showed unique performance compared with bare chitosan film. The incorporated nano-silver could improve the strength properly. The results revealed that AgNWs in CS film, improved its tensile strength more than 62% and Young modulus 55% compared with pure chitosan film. On the other hand tensile strength was increased 36.7% with AgNPs. Importantly, the film also exhibited conductivity and antibacterial properties, which may expand its future application.

  19. Antimicrobial and antitumor activities of chitosan from shiitake stipes, compared to commercial chitosan from crab shells.

    Science.gov (United States)

    Chien, Rao-Chi; Yen, Ming-Tsung; Mau, Jeng-Leun

    2016-03-15

    Chitosan was prepared by alkaline N-deacetylation of chitin obtained from shiitake stipes and crab shells and its antimicrobial and antitumor activities were studied. Chitosan from shiitake stipes and crab shells exhibited excellent antimicrobial activities against eight species of Gram positive and negative pathogenic bacteria with inhibition zones of 11.4-26.8mm at 0.5mg/ml. Among chitosan samples, shiitake chitosan C120 was the most effective with inhibition zones of 16.4-26.8mm at 0.5mg/ml. In addition, shiitake and crab chitosan showed a moderate anti-proliferative effect on IMR 32 and Hep G2 cells. At 5mg/ml, the viability of IMR 32 cells incubated with chitosan was 68.8-85.0% whereas that of Hep G2 cells with chitosan was 60.4-82.9%. Overall, shiitake chitosan showed slightly better antimicrobial and antitumor activities than crab chitosan. Based on the results obtained, shiitake and crab chitosan were strong antimicrobial agents and moderate antitumor agents.

  20. Comparative study on the effects of negatively-charged biopolymers on chitosan-based gels for the development of instantaneous gels

    International Nuclear Information System (INIS)

    Polymeric electrolytic complexes are solutions of charged/ionized chains. These solutions of positive and negative charge can be combined to make instantaneous networks bonded by electrostatic interactions, a gel network. These electrostatic interaction allows for easy application in injectable gels as the network can be temporarily distributed with the application of force and reformed on the relief of it. Possible applications for these injectable gels include drug delivery and wound-healing. κ-Carrageenan, dextran sulfate, alginate, and chitosan are polyelectrolytic biocompatible polymers which are widely studied and used for a variety of biomedical applications. Gel networks are made by combining a negatively-charged (κ-Carrageenan, dextran sulfate, or alginate) and positively charged (chitosan) solutions. The strong electrostatic interaction between the opposite charges from the gel network and the inherent biocompatibility of the polymers allow future biomedical applications. Quat 188-modified chitosan has additional sites for electrostatic bonding, can be dissolved in neutral, basic, and acidic pH, and has shown inherent antibacterial activity. The objectives of this study are the following: to formulate chitosan-based gels mixing solutions of chitosan with solutions of either κ-Carrageenan, dextran sulfate, or alginate, study the gelation of the gels as function of time and pH (4, 7, and 9) using UV-Vis, characterize the chitosan-based gels through DSC and DMA, characterize the physiological degradation of the chitosan-based gels, and compare results with those from Quat 188-modified chitosan-based gels. Polyelectrolytic solutions of chitosan and negatively-charged biopolymer of similar viscosities were mixed. It was determined from the UV-Vis spectroscopy of the chitosan-carrageenan gels under pH7 buffer that the increase of concentration by a factor of 5 for 0.006M-0.0095M and 1.25 for 0.0095M-0.0150M Chitosan-Carrageenan gels improved gelation by the

  1. The Role of Nitrogen and Sulfur Interaction in Maize Quality(Zea mays L. )

    Institute of Scientific and Technical Information of China (English)

    XIE Rui-zhi; DONG Shu-ting; HU Chang-hao; WANG Kong-jun

    2003-01-01

    Two hybrids of maize with different responses to sulfur were used in the pool experiment. Theeffects of nitrogen and sulfur on the grain quality of maize were evaluated. The results indicated that grainquality changed with the nutrition supply. The contents of proteins, amino acids, soluble sugar, crude fat,But the effects of nitrogen and sulfur were not the same. Nitrogen increased starch content of the grain, but Sdecreased the content. Both N and S enhanced the proportion of amylopectin in starch. Sulfur nutrition signif-icantly improved the grain quality of maize when a large amount of nitrogen was used together. Both hybridshad similar response to N and S treatments.

  2. Effects of Chitosan Concentration on the Protein Release Behaviour of Electrospun Poly(ε-caprolactone)/Chitosan Nanofibers

    OpenAIRE

    Fatemeh Roozbahani; Naznin Sultana; Davood Almasi; Farnaz Naghizadeh

    2015-01-01

    Poly(ε-caprolactone)/chitosan (PCL/chitosan) blend nanofibers with different ratios of chitosan were electrospun from a formic acid/acetic acid (FA/AA) solvent system. Bovine serum albumin (BSA) was used as a model protein to incorporate biochemical cues into the nanofibrous scaffolds. The morphological characteristics of PCL/chitosan and PCL/chitosan/BSA Nanofibers were investigated by scanning electron microscopy (SEM). Fourier transform infrared spectroscopy (FTIR) was used to detect the p...

  3. Thermal behavior and properties of chitosan fibers enhanced polysaccharide hydrogels

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Limei, E-mail: 20134014002@stu.suda.edu.cn [Institute of Functional Nano and Soft Materials (FUNSOM), Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou, Jiangsu 215123 (China); Wang, Binghao, E-mail: 20104209162@suda.edu.cn [Institute of Functional Nano and Soft Materials (FUNSOM), Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou, Jiangsu 215123 (China); Bai, Tong-chun, E-mail: tcbai@suda.edu.cn [School of Chemistry, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, Jiangsu 215123 (China); Dong, Bin, E-mail: bdong@suda.edu.cn [Institute of Functional Nano and Soft Materials (FUNSOM), Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou, Jiangsu 215123 (China)

    2014-05-01

    Graphical abstract: - Highlights: • Chitosan, in fiber form, was introduced into polysaccharide hydrogels. • Strong interactions in hybrid hydrogels are systematically investigated. • Dehydration activation energy decreases as the content of CSFs increases. • Chitosan fibers improved hydrogels’ structural stability and storage modulus. - Abstract: Composite hydrogel based on chitosan fibers (CSFs), high- and low-acyl gellan gum (HLG) was fabricated. The strong interactions between CSFs and HLG were confirmed by Fourier transform infrared (FTIR) spectra, X-ray diffraction (XRD) and thermogravimetric (TG) analysis. Differential scanning calorimetry (DSC) study shows that the dehydration activation energy decreases as the content of CSFs increases. The rheological measurement showed that the storage modulus of 2.0CSF–HLG (where 2.0 represents the mass ratio between CSF and HLG) hydrogels is 48 kPa at regular frequency of 1 rad/s, which is 1.8 times higher than that of HLG hydrogel. In addition, the SEM images demonstrated that 2.0CSF–HLG hydrogel exhibits three dimensional architectures with HLG attaching to CSFs. A weak swelling capacity of CSF–HLG hydrogels was observed, indicating fibroid CSFs would hinder the movement of HLG chain segments in solution.

  4. Alginate Hydrogels Coated with Chitosan for Wound Dressing

    Directory of Open Access Journals (Sweden)

    Maria Cristina Straccia

    2015-05-01

    Full Text Available In this work, a coating of chitosan onto alginate hydrogels was realized using the water-soluble hydrochloride form of chitosan (CH-Cl, with the dual purpose of imparting antibacterial activity and delaying the release of hydrophilic molecules from the alginate matrix. Alginate hydrogels with different calcium contents were prepared by the internal setting method and coated by immersion in a CH-Cl solution. Structural analysis by cryo-scanning electron microscopy was carried out to highlight morphological alterations due to the coating layer. Tests in vitro with human mesenchymal stromal cells (MSC were assessed to check the absence of toxicity of CH-Cl. Swelling, stability in physiological solution and release characteristics using rhodamine B as the hydrophilic model drug were compared to those of relative uncoated hydrogels. Finally, antibacterial activity against Escherichia coli was tested. Results show that alginate hydrogels coated with chitosan hydrochloride described here can be proposed as a novel medicated dressing by associating intrinsic antimicrobial activity with improved sustained release characteristics.

  5. Alginate hydrogels coated with chitosan for wound dressing.

    Science.gov (United States)

    Straccia, Maria Cristina; d'Ayala, Giovanna Gomez; Romano, Ida; Oliva, Adriana; Laurienzo, Paola

    2015-05-11

    In this work, a coating of chitosan onto alginate hydrogels was realized using the water-soluble hydrochloride form of chitosan (CH-Cl), with the dual purpose of imparting antibacterial activity and delaying the release of hydrophilic molecules from the alginate matrix. Alginate hydrogels with different calcium contents were prepared by the internal setting method and coated by immersion in a CH-Cl solution. Structural analysis by cryo-scanning electron microscopy was carried out to highlight morphological alterations due to the coating layer. Tests in vitro with human mesenchymal stromal cells (MSC) were assessed to check the absence of toxicity of CH-Cl. Swelling, stability in physiological solution and release characteristics using rhodamine B as the hydrophilic model drug were compared to those of relative uncoated hydrogels. Finally, antibacterial activity against Escherichia coli was tested. Results show that alginate hydrogels coated with chitosan hydrochloride described here can be proposed as a novel medicated dressing by associating intrinsic antimicrobial activity with improved sustained release characteristics.

  6. Thermal behavior and properties of chitosan fibers enhanced polysaccharide hydrogels

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Chitosan, in fiber form, was introduced into polysaccharide hydrogels. • Strong interactions in hybrid hydrogels are systematically investigated. • Dehydration activation energy decreases as the content of CSFs increases. • Chitosan fibers improved hydrogels’ structural stability and storage modulus. - Abstract: Composite hydrogel based on chitosan fibers (CSFs), high- and low-acyl gellan gum (HLG) was fabricated. The strong interactions between CSFs and HLG were confirmed by Fourier transform infrared (FTIR) spectra, X-ray diffraction (XRD) and thermogravimetric (TG) analysis. Differential scanning calorimetry (DSC) study shows that the dehydration activation energy decreases as the content of CSFs increases. The rheological measurement showed that the storage modulus of 2.0CSF–HLG (where 2.0 represents the mass ratio between CSF and HLG) hydrogels is 48 kPa at regular frequency of 1 rad/s, which is 1.8 times higher than that of HLG hydrogel. In addition, the SEM images demonstrated that 2.0CSF–HLG hydrogel exhibits three dimensional architectures with HLG attaching to CSFs. A weak swelling capacity of CSF–HLG hydrogels was observed, indicating fibroid CSFs would hinder the movement of HLG chain segments in solution

  7. Dyeing Characteristics of Chitosan Biguanidine Hydrochloride Treated Wool Fabrics

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Chitosan biguanidine hydrochloride(CGH) has been synthesized by the guanidineylation reaction of chitosan with dicyandiamide.The structures of CGH were characterized by Fourier transform infrared spectroscopy and 13CNMR spectra.In this paper,we used citric acid(CA) as a crosslinking agent,mixed with CGH to perform a pad-drycure treatment on wool fabric to study reaction mechanism during crosslinking with the help of Fourier transform infrared spectroscopy(FT-IR) and scanning electron microscopy(SEM).Dyeing characteristics of CGH treated wool fabric was assessed.The effects of CGH concentration,curing temperature,dipping time,pH value on color yield of reactive dyes on wool fibres were investigated.Fastness properties of the modified wool fabric to laundering and crocking have also been discussed.Fourier transform infrared spectroscopy(FT-IR) showed that CA produce esterification with the-OH group of the wool and transamidation with the-NH2 group of the CGH to form a crosslink.Scanning electron microscopy(SEM) analysis showed the CGH firmly attached to the surface of wool fibre.It was found that the CGH pretreated wool fabrics had significantly improved dyeability characteristics.It is worthwhile to mention that the CGH treated samples have antibacterial potential due to the antibacterial property of chitosan molecules and guanidinium salts.

  8. One-step electrospinning of cross-linked chitosan fibers.

    Science.gov (United States)

    Schiffman, Jessica D; Schauer, Caroline L

    2007-09-01

    Chitin is a nitrogen-rich polysaccharide that is abundant in crustaceans, mollusks, insects, and fungi and is the second most abundant organic material found in nature next to cellulose. Chitosan, the N-deacetylated derivative of chitin, is environmentally friendly, nontoxic, biodegradable, and antibacterial. Fibrous mats are typically used in industries for filter media, catalysis, and sensors. Decreasing fiber diameters within these mats causes many beneficial effects such as increased specific surface area to volume ratios. When the intrinsically beneficial effects of chitosan are combined with the enhanced properties of nanofibrous mats, applications arise in a wide range of fields, including medical, packaging, agricultural, and automotive. This is particularly important as innovative technologies that focus around bio-based materials are currently of high urgency, as they can decrease dependencies on fossil fuels. We have demonstrated that Schiff base cross-linked chitosan fibrous mats can be produced utilizing a one-step electrospinning process that is 25 times faster and, therefore, more economical than a previously reported two-step vapor-cross-linking method. These fibrous mats are insoluble in acidic, basic, and aqueous solutions for 72 h. Additionally, this improved production method results in a decreased average fiber diameter, which measures 128 +/- 40 nm. Chemical and structural analyses were conducted utilizing Fourier transform infrared spectroscopy, solubility studies, and scanning electron microscopy. PMID:17696400

  9. New inoculants on maize silage fermentation

    Directory of Open Access Journals (Sweden)

    Fábia Giovana do Val de Assis

    2014-08-01

    Full Text Available The objective of this study was to evaluate the effect of bacterial inoculants at two inoculation rates on chemical and biological characteristics of maize silage. The treatments consisted of two inoculating rates (5 and 6 log cfu g-1 of forage for each strain of lactic acid bacteria (LAB identified as Lactobacillus buchneri, L. hilgardii, or L. plantarum. The maize was ensiled in experimental PVC silos. Samples were taken for the determination of the contents of dry matter (DM, crude protein (CP, neutral detergent fiber (NDF, water-soluble carbohydrates (WSC, organic acids and alcohols, for the evaluation of the populations of lactic acid bacteria, yeasts, filamentous fungi, and for the determination of pH values during ensilage and after 30 or 90 days of fermentation. The doses of inoculants did not promote significant differences on the evaluated characteristics. There was effect of inoculants on acetic acid, 1.2-propanediol, LAB population, filamentous fungi, and pH value. No significant influence of the treatments with inoculants was observed in the variables DM, WSC, CP, lactic acid concentrations, or ethanol. The maximum temperature, i.e., the time to achieve the maximum temperature (TMT and aerobic stability (AS, was not influencied by treatments. However, a decrease in maximum temperature, an increase in TMT, and improvement in the AS were observed after 90 days of fermentation. These results proved the advantage of microbial inoculation. The treatments influenced LAB populations and filamentous fungi, but no effect was observed on the yeast population. The best inoculation dose is 6 cfu g-1 of forage because it provides higher reduction of filamentous fungi in maize silage, thereby decreasing the aerobic deterioration by these microorganisms.

  10. Functional modification of chitosan for biomedical application

    Science.gov (United States)

    Tang, Ruogu

    Chitosan is a linear polysaccharide. Normally commercial chitosan consists of randomly distributed beta-(1-4)-linked D-glucosamine (deacetylated proportion) and N-acetyl-D-glucosamine (acetylated proportion) together. Chitosan has been proved to be a multifunctional biopolymer that presents several unique properties due to free amino groups in the repeating unit therefore chitosan has been widely applied in various areas. To be specific, provided by the excellent biocompatibility, chitosan is expected to be used in biological and medical applications including wound dressing, implants, drug carrier/delivery, etc. In this thesis, we worked on chitosan functionalization for biomedical application. The thesis are composed of three parts: In the first part, we focused on modifying the chitosan thin film, chemically introducing the nitric oxide functional groups on chitosan film. We covalently bonded small molecule diazeniumdiolates onto the chitosan films and examined the antimicrobial function and biocompatibility. Commercial chitosan was cast into films from acidic aqueous solutions. Glutaraldehyde reacted with the chitosan film to introduce aldehyde groups onto the chitosan film (GA-CS film). GA-CS reacted with a small molecule NO donor, NOC-18, to covalently immobilize NONO groups onto the polymer (NO-CS film). The-CHO and [NONO] group were verified by FT IR, UV and Griess reagent. The NO releasing rate in aqueous solution and and thermal stability were studied quantitatively to prove its effectiveness. A series of antimicrobial tests indicated that NO-CS films have multiple functions: 1. It could inhibit the bacteria growth in nutrient rich environment; 2. It could directly inactivate bacteria and biofilm; 3. It could reduce the bacteria adherence on the film surface as well as inhibit biofilm formation. In addition, the NO-CS film was proved to be biocompatible with cell and it was also compatible with other antibiotics like Amoxicillin. In the second part, we

  11. Natural-Synthetic Hybrid Polymers Developed via Electrospinning: The Effect of PET in Chitosan/Starch System

    Directory of Open Access Journals (Sweden)

    Carlos Velasco-Santos

    2011-03-01

    Full Text Available Chitosan is an amino polysaccharide found in nature, which is biodegradable, nontoxic and biocompatible. It has versatile features and can be used in a variety of applications including films, packaging, and also in medical surgery. Recently a possibility to diversify chitosan properties has emerged by combining it with synthetic materials to produce novel natural-synthetic hybrid polymers. We have studied structural and thermophysical properties of chitosan + starch + poly(ethylene terephthalate (Ch + S + PET fibers developed via electrospinning. Properties of these hybrids polymers are compared with extant chitosan containing hybrids synthesized by electrospinning. Molecular interactions and orientation in the fibers are analyzed by infrared and Raman spectroscopies respectively, morphology by scanning electron microscopy and thermophysical properties by thermogravimetric analysis and differential scanning calorimetry. Addition of PET to Ch + S systems results in improved thermal stability at elevated temperatures.

  12. 3D composites based on the blends of chitosan and collagen with the addition of hyaluronic acid.

    Science.gov (United States)

    Sionkowska, Alina; Kaczmarek, Beata; Lewandowska, Katarzyna; Grabska, Sylwia; Pokrywczyńska, Marta; Kloskowski, Tomasz; Drewa, Tomasz

    2016-08-01

    3D porous composites based on blends of chitosan, collagen and hyaluronic acid were obtained through the lyophilization process. Mechanical properties, swelling behavior and thermal stability of the blends were studied. Moreover, SEM images were taken and the structure of the blends was studied. Biological properties of the materials obtained were investigated by analyzing of proliferation rate of fibroblast cells incubated with biomaterial extract using MTT assay (3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide). The results showed that the properties of 3D composites based on the blends of chitosan and collagen were altered after the addition 1%, 2% and 5% of hyaluronic acid. Mechanical properties and thermal stability of chitosan/collagen blends were improved in the presence of hyaluronic acid in the composite. New 3D materials based on the blends of chitosan, collagen and hyaluronic acid were non-toxic and did not significantly affect cell morphology. PMID:27151670

  13. MONTHLY PRICE ANALYSIS OF COWPEA (BEANS AND MAIZE IN AKWA IBOM STATE, SOUTHERN NIGERIA

    Directory of Open Access Journals (Sweden)

    Sunday Brownson Akpan

    2014-04-01

    on the findings, it is recommended that, the Akwa Ibom State government should continue to provide marketing infrastructures and reduced externality costs in order to improve further the symmetric nature of information flow among Maize and Beans markets in the state. Also, individuals, trade unions, NGOs’ and government should established market information units and awareness programmes on mass media to facilitate efficient communication flows of Beans and Maize markets in the state.

  14. The effect of chitosan concentration on the electrical property of chitosan-blended cellulose electroactive paper

    International Nuclear Information System (INIS)

    We studied the effect of chitosan blending on the electrical property of chitosan-blended cellulose electroactive paper (EAPap) under different humidity conditions. As the chitosan blending ratio increased, the real part of the dielectric constant of chitosan-blended cellulose EAPap increased while the dielectric loss factor decreased. From the curve fitting of the measured data using an electrode polarization model, it was found that increasing the chitosan ratio in the EAPap might promote a decrease in the relaxation time of the EAPap, resulting in an increase of the ion mobility and dc conductivity. Over 30% of the chitosan blending ratio, a gradual increment of the ion mobility of the EAPap was observed at 40% relative humidity, while a quadratic increment of the mobility was found at 60% relative humidity condition. This kind of ion-mobility-enhanced cellulose EAPap can be used not only for bending actuators but also for medical applications such as blood clotting patches

  15. Genetic diversity among yellow maize with pro-vitamin A content

    Directory of Open Access Journals (Sweden)

    Mercy Oluremi Olowolafe

    2016-06-01

    Full Text Available An improvement in the concentration of vitamin A in adapted yellow maize varieties grown in Africa can have a positive impact on the dietary intakes in regions where maize is a staple food. The present study was designed to identify heterotic groups and divergent parents for developing new pro-vitamin A enriched maize lines. Ten Simple Sequence Repeats (SSR markers were used to generate DNA profiles among thirteen commonly grown yellow maize lines across south western Nigeria and three high pro-vitamin A lines from International Institute of Tropical Agriculture (IITA, Ibadan. The result obtained estimated 100% polymorphism among the ten SSR markers with polymorphic information content that ranged from 0.28 to 0.71 on an average of 0.50. Genetic similarity coefficients among the 16 maize lines varied from 0.28 to 0.92 GS with an average of 0.63 GS. Four well defined groups were identified at 0.65 GS with an IITA line, PVA8, solely, formed a group. The study identified PVA8 and its most three distant relatives as potential divergent parents that could serve as important genetic resources for broadening the genetic base of the presently assessed IAR&T maize collections and also to develop new maize lines with higher level of pro-vitamin A content.

  16. Glycemic responses to maize flour stiff porridges prepared using local recipes in Malawi.

    Science.gov (United States)

    Mlotha, Vincent; Mwangwela, Agnes Mbachi; Kasapila, William; Siyame, Edwin W P; Masamba, Kingsley

    2016-03-01

    Glycemic index is defined as the incremental area under the blood glucose response curve of a 50 g carbohydrate portion of a test food expressed as a percent of the response to the same amount of carbohydrate from a standard food taken by the same subject. This study investigated glycemic index of maize stiff porridges consumed as staple food in Malawi and a large majority of other countries in sub-Saharan Africa to identify areas for improvement in consumer diets. Stiff porridges were prepared using flour from whole maize, maize grits, and fermented maize grits. The porridges were served to 11 healthy volunteers for 3 weeks, with two serving sessions a week. Glucose was served as a reference food during weekly serving sessions. Results from descriptive analysis revealed that glycemic responses varied across subjects and porridge types. Porridge prepared from fermented maize grits had moderate glycemic index of 65.49 and was comparable in nutrient composition and sensory characteristics with the other test porridges. Glycemic indices of the porridges prepared from whole maize flour and grits were high at 94.06 and 109.64, respectively, attributed to the effect of traditional maize flour processing, preparation, and cooking methods used. The study also calculated glyaemic load of the porridges and drew recommendations to inform diet planning and modifications for healthy and diabetic individuals. PMID:27004122

  17. Proline, glycine betaine, total phenolics and pigment contents in response to osmotic stress in maize seedlings

    Directory of Open Access Journals (Sweden)

    SAJJAD MOHARRAMNEJAD

    2015-12-01

    Full Text Available In order to evaluate the fresh weight, RWC, pigment content, total phenolics, proline and glycine betaine responses of maize inbred lines to osmotic stress, a factorial experiment was carried out under laboratory conditions with two maize inbred lines (B73 and MO17 and two osmotic stress levels induced by PEG (control and -0.6 MPa. Fresh weight significantly decreased under drought stress. On the basis of percent inhibition in fresh weight at the osmotic stress MO17 was ranked as tolerant (inhibition 45.30%, and B73 drought sensitive (inhibition more than 50%. Leaf relative water content (RWC was significantly decreased in both inbred lines under osmotic stress. The pigment concentrations were substantially declined in both maize inbreds under osmotic stressed conditions. However, this reduction was less in B73 than MO17. Osmoitc stress declined the levels of total phenolics in both maize inbreds. On the other hand, the osmotic stress markedly enhanced the levels of proline and glycine betaine in both maize inbreds, but this was more pronounced in MO17. The present results showed that osmotic stress retards the growth and some biochemical attributes of maize inbreds. In conclusion, the level of proline and glycine betaine in maize could improve drought tolerance.

  18. MaizeGDB update: new tools, data and interface for the maize model organism database.

    Science.gov (United States)

    Andorf, Carson M; Cannon, Ethalinda K; Portwood, John L; Gardiner, Jack M; Harper, Lisa C; Schaeffer, Mary L; Braun, Bremen L; Campbell, Darwin A; Vinnakota, Abhinav G; Sribalusu, Venktanaga V; Huerta, Miranda; Cho, Kyoung Tak; Wimalanathan, Kokulapalan; Richter, Jacqueline D; Mauch, Emily D; Rao, Bhavani S; Birkett, Scott M; Sen, Taner Z; Lawrence-Dill, Carolyn J

    2016-01-01

    MaizeGDB is a highly curated, community-oriented database and informatics service to researchers focused on the crop plant and model organism Zea mays ssp. mays. Although some form of the maize community database has existed over the last 25 years, there have only been two major releases. In 1991, the original maize genetics database MaizeDB was created. In 2003, the combined contents of MaizeDB and the sequence data from ZmDB were made accessible as a single resource named MaizeGDB. Over the next decade, MaizeGDB became more sequence driven while still maintaining traditional maize genetics datasets. This enabled the project to meet the continued growing and evolving needs of the maize research community, yet the interface and underlying infrastructure remained unchanged. In 2015, the MaizeGDB team completed a multi-year effort to update the MaizeGDB resource by reorganizing existing data, upgrading hardware and infrastructure, creating new tools, incorporating new data types (including diversity data, expression data, gene models, and metabolic pathways), and developing and deploying a modern interface. In addition to coordinating a data resource, the MaizeGDB team coordinates activities and provides technical support to the maize research community. MaizeGDB is accessible online at http://www.maizegdb.org. PMID:26432828

  19. Staple Crops, Smallholder Farmers and Multinationals: The ‘Water-Efficient Maize for Africa’ Project

    OpenAIRE

    Lumpkin, Thomas A.; Armstrong, Janice

    2009-01-01

    Doubling food production by 2050 under conditions of climate change and depleted natural resources requires increased investment and creative approaches. The Water-Efficient Maize for Africa (WEMA) project, a five-year public–private partnership begun in 2008 and led by the African Agricultural Technology Foundation (AATF), is an excellent example. Under WEMA, Monsanto, the International Maize and Wheat Improvement Center (CIMMYT), and national agricultural research systems in Kenya, Mozambiq...

  20. Seed quality and water use characteristics of maize landraces compared with selected commercial hybrids

    OpenAIRE

    Farai Mazvimbakupa; Albert Thembinkosi Modi; Tafadzwanashe Mabhaudhi

    2015-01-01

    Understanding seed quality and water use characteristics of maize (Zea mays L.) landraces will improve food security among subsistence farmers who still cultivate them. The objective of this study was to evaluate seed quality and water use characteristics of two maize landraces (GQ1 and GQ2) compared with two commercial hybrids (SC701 and PAN53). Seed quality was determined by the standard germination, electrical conductivity, and tetrazolium tests. A controlled environment study was conducte...

  1. Variability of factors that affect availability of iron, manganese and zinc in maize lines

    OpenAIRE

    Dragičević Vesna; Mladenović-Drinić Snežana; Stojiljković Milovan; Filipović Milomir; Dumanović Zoran; Kovačević Dragan

    2013-01-01

    Deficiencies of some mineral elements are causing serious health problems, which could be prevented by increase of mineral nutrients in food with supplementation, food fortification or plant breeding. From this point, experiment with 78 maize inbred lines was set up to determine maize lines with improved contents of Fe, Zn and Mn, as well as their relations with phytic acid, inorganic phosphorus and β-carotene, as factors which affect their absorption. Obta...

  2. Increased maize yield using slow-release attapulgite-coated fertilizers

    OpenAIRE

    Guan, Yu; Song, Chao; Gan, Yantai; Li, Feng-Min

    2014-01-01

    International audience Slow-release fertilizers could improve the productivity of field crops and reduce environmental pollution. So far, no slow-release fertilizers are suited for maize cultivation in semiarid areas of China. Therefore, we tested attapulgite-coated fertilizers. Attapulgite-coated fertilizers were prepared by dividing chemical fertilizers into three parts according to the nutrient demand of maize in its three main growth stages and coating each part with a layer of attapul...

  3. Chitosan-Coated Magnetic Nanoparticles with Low Chitosan Content Prepared in One-Step

    OpenAIRE

    Yolanda Osuna; Karla M. Gregorio-Jauregui; J. Gerardo Gaona-Lozano; de la Garza-Rodríguez, Iliana M.; Anna Ilyna; Enrique Díaz Barriga-Castro; Hened Saade; López, Raúl G.

    2012-01-01

    Chitosan-coated magnetic nanoparticles (CMNP) were obtained at 50°C in a one-step method comprising coprecipitation in the presence of low chitosan content. CMNP showed high magnetization and superparamagnetism. They were composed of a core of 9.5 nm in average diameter and a very thin chitosan layer in accordance with electron microscopy measurements. The results from Fourier transform infrared spectrometry demonstrated that CMNP were obtained and those from thermogravimetric analysis allowe...

  4. Adsorption of fucoidan and chitosan sulfate on chitosan modified PET films monitored by QCM-D

    OpenAIRE

    Indest, Tea; Laine, Janne; Johansson, Leena Sisko; Stana-Kleinschek, Karin; Strnad, Simona; Dworczak, Renate; Ribitsch, Volker

    2012-01-01

    The adsorption behavior of fucoidan as well as chitosan derivatives (chitosan sulfate) on poly(ethylene terephthalate) (PET) model film surface was studied using the quartz crystal microbalance technique. These systems were chosen for this study due to their promising biocompatible properties. Moreover, fucoidan and chitosan sulfate have promising anticoagulant properties and represent an alternative to heparin treatment of vascular grafts. As a first step, PET foils were activated by alkalin...

  5. Structure and Function of Chitosan (V). Conformations of Ethylene Glycol Derivatives of Chitin and Chitosan

    OpenAIRE

    YUI, Toshifumi; NAKATA, Kunihiko; OGAWA, Kozo

    1996-01-01

    Molecular structures of ethylene glycol derivatives of chitin and chitosan, where 0-6 of chitin chain was etherified and both 0-3 and 0-6 of chitosan were substituted, were studied by X-ray fiber diffraction methods coupled with conformational analyses. The extended two-fold helical conformations of both chitin and chitosan chains were retained even by the etherifications. Possible molecular conformations of these derivatives were proposed.

  6. Chitosan: a propitious biopolymer for drug delivery.

    Science.gov (United States)

    Duttagupta, Dibyangana S; Jadhav, Varsha M; Kadam, Vilasrao J

    2015-01-01

    Scientists have always been interested in the use of natural polymers for drug delivery. Chitosan, being a natural cationic polysaccharide has received a great deal of attention in the past few years. It is obtained by deacetylation of chitin and is regarded as the second most ubiquitous polymer subsequent to cellulose on earth. Unlike other natural polymers, the cationic charge possessed by chitosan is accountable for imparting interesting physical and chemical properties. Chitosan has been widely exploited for its mucoadhesive character, permeation enhancing properties and controlled release of drugs. Moreover it's non-toxic, biocompatible and biodegradable properties make it a good candidate for novel drug delivery system. This review provides an insight on various chitosan based formulations for drug delivery. Some of the current applications of chitosan in areas like ophthalmic, nasal, buccal, sublingual, gastro-retentive, pulmonary, transdermal, colon-specific and vaginal drug delivery have been discussed. In addition, active targeting of drugs to tumor cells using chitosan has been described. Lastly a brief section covering the safety aspects of chitosan has also been reviewed. PMID:25761010

  7. Coloration of cotton fibers using nano chitosan.

    Science.gov (United States)

    Wijesena, Ruchira N; Tissera, Nadeeka D; de Silva, K M Nalin

    2015-12-10

    A method of coloration of cotton fabrics with nano chitosan is proposed. Nano chitosan were prepared using crab shell chitin nanofibers through alkaline deacetylation process. Average nano fiber diameters of nano chitosan were 18 nm to 35 nm and the lengths were in the range of 0.2-1.3 μm according to the atomic force microscope study. The degree of deacetylation of the material was found to be 97.3%. The prepared nano chitosan dyed using acid blue 25 (2-anthraquinonesulfonic acid) and used as the coloration agent for cotton fibers. Simple wet immersion method was used to color the cotton fabrics by nano chitosan dispersion followed by acid vapor treatment. Scanning electron microscope and atomic force microscope study of the treated cotton fiber revealed that the nano chitosan were consistently deposited on the cotton fiber surface and transformed in to a thin polymer layer upon the acid vapor treatment. The color strength of the dyed fabrics could be changed by changing the concentration of dyed nano chitosan dispersion. PMID:26428115

  8. Coloration of cotton fibers using nano chitosan.

    Science.gov (United States)

    Wijesena, Ruchira N; Tissera, Nadeeka D; de Silva, K M Nalin

    2015-12-10

    A method of coloration of cotton fabrics with nano chitosan is proposed. Nano chitosan were prepared using crab shell chitin nanofibers through alkaline deacetylation process. Average nano fiber diameters of nano chitosan were 18 nm to 35 nm and the lengths were in the range of 0.2-1.3 μm according to the atomic force microscope study. The degree of deacetylation of the material was found to be 97.3%. The prepared nano chitosan dyed using acid blue 25 (2-anthraquinonesulfonic acid) and used as the coloration agent for cotton fibers. Simple wet immersion method was used to color the cotton fabrics by nano chitosan dispersion followed by acid vapor treatment. Scanning electron microscope and atomic force microscope study of the treated cotton fiber revealed that the nano chitosan were consistently deposited on the cotton fiber surface and transformed in to a thin polymer layer upon the acid vapor treatment. The color strength of the dyed fabrics could be changed by changing the concentration of dyed nano chitosan dispersion.

  9. Chitosan Nanoparticles Prepared by Ionotropic Gelation: An Overview of Recent Advances.

    Science.gov (United States)

    Desai, Kashappa Goud

    2016-01-01

    The objective of this review is to summarize recent advances in chitosan nanoparticles prepared by ionotropic gelation. Significant progress has occurred in this area since the method was first reported. The gelation technique has been improved through a number of creative methodological modifications. Ionotropic gelation via electrospraying and spinning disc processing produces nanoparticles with a more uniform size distribution. Large-scale manufacturing of the nanoparticles can be achieved with the latter approach. Hydrophobic and hydrophilic drugs can be simultaneously encapsulated with high efficiency by emulsification followed by ionic gelation. The turbulent mixing approach facilitates nanoparticle formation at a relatively high polymer concentration (5 mg/mL). The technique can be easily tuned to achieve the desired polymer/surface modifications (e.g., blending, coating, and surface conjugation). Using factorial-design-based approaches, optimal conditions for nanoparticle formation can be determined with a minimum number of experiments. New insights have been gained into the mechanism of chitosan-tripolyphosphate nanoparticle formation. Chitosan nanoparticles prepared by ionotropic gelation tend to aggregate/agglomerate in unfavorable environments. Factors influencing this phenomenon and strategies that can be adopted to minimize the instability are discussed. Ionically cross-linked nanoparticles based on native chitosan and modified chitosan have shown excellent efficacy for controlled and targeted drug-delivery applications. PMID:27651100

  10. Structural analysis, and antioxidant and antibacterial properties of chitosan-poly (vinyl alcohol) biodegradable films.

    Science.gov (United States)

    Hajji, Sawssen; Chaker, Achraf; Jridi, Mourad; Maalej, Hana; Jellouli, Kemel; Boufi, Sami; Nasri, Moncef

    2016-08-01

    The development and characterization of biodegradable blend films based on chitosan and poly (vinyl alcohol) for possible use in a variety of biological activities are reported. Fourier transform infrared spectroscopy (FTIR) spectra of chitosan-poly (vinyl alcohol) (Ch/PVA) films showed characteristics peaks shifting to a lower frequency range due to hydrogen bonding between -OH of PVA and -NH2 of chitosan. The chitosan and PVA polymers presented good compatibility. The morphology study of chitosan and composite films showed a compact and homogenous structure. The tensile strength and elongation at break increased with PVA content. In fact, the highest tensile strength and elongation at break (53.58 MPa and 454 %) occurs with pure PVA film. The results showed that PVA incorporation in the blends contributes to increase the intermolecular interactions, thus improving the mechanical properties. In addition, the prepared films demonstrated high antioxidant activities monitored by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging, reducing power, and β-carotene bleaching activity. Nevertheless, PVA addition reduced antioxidant and antibacterial activities against Gram-positive and Gram-negative bacteria tested. PMID:27106077

  11. Behavior of MC3T3-E1 Osteoblast Cultured on Chitosan Modified with Polyvinylpyrrolidone

    Institute of Scientific and Technical Information of China (English)

    XI Jing; GAO Yuan; KONG Lijun; GONG Yandao; ZHAO Nanming; ZHANG Xiufang

    2005-01-01

    The physical and chemical properties of four kinds of modified chitosan materials made by blending chitosan with polyvinylpyrrolidone (PVP) were investigated. All four of these modified chitosan materials were hydrophilic with water contact angles ranging from 59° to 69°. Fourier transform-infrared spectra of the modified materials showed a new band at 1288 cm-1, implying formation of a surface physical interpenetrating network structure. Enzyme linked immunosorbent assay results indicated that much less fibronectin was adsorbed on the modified materials than on only chitosan. The viability of MC3T3-E1 osteoblasts cultured on the materials was assessed by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl- 2H-tetrazolium bromide assay. The results show that adding PVP10000 into the chitosan promotes adhesion of MC3T3-E1 osteoblasts on the modified materials, but has no effect on cell growth and proliferation; while adding PVP40000 reduces cell adhesion, growth, and proliferation. The results suggest that the increased hydrophilicity of the material surface does not always improve its biocompatibility, which will influence the selection and design of biomaterials.

  12. Effects of chitosan-glucose complex coating on postharvest quality and shelf life of table grapes.

    Science.gov (United States)

    Gao, Pisheng; Zhu, Zhiqiang; Zhang, Ping

    2013-06-01

    Surface coatings and films are prospective alternatives for extending the postharvest life of fresh fruits and vegetables. In this study, freshly harvested grapes were treated with chitosan, glucose, chitosan-glucose complex (CGC), or water (control) for up to 60 days at 0 °C in 95% relative humidity followed by 3 days in the air at 20 °C. The results showed that coated samples were effective in terms of senescence inhibition and postharvest diseases prevention. Chitosan-glucose complex showed better effects on delaying the declines of total soluble solids, ascorbic acid and titratable acidity, decreasing decay and weight loss, suppressing respiration rate, inducing POD and SOD activities, in comparison with pure chitosan or glucose. In addition, CGC coating treatment ensured better berry texture and higher sensory scores, compared with those treated with chitosan or glucose alone. The results indicated that CGC may be a promising strategy for improving the postharvest quality and extending the shelf life of table grapes. PMID:23618282

  13. Chitosan and its oligosaccharide derivatives (chito-oligosaccharides) as feed supplements in poultry and swine nutrition.

    Science.gov (United States)

    Swiatkiewicz, S; Swiatkiewicz, M; Arczewska-Wlosek, A; Jozefiak, D

    2015-02-01

    Chitosan is a non-toxic polyglucosamine, widespread in nature, which is deacetylated to varying degrees form of chitin, a component of exoskeleton of shrimps, crabs and insects. Because chitosan contains reactive functional groups, that is, amino acids and hydroxyl groups, it is characterised by antimicrobial, anti-inflammatory, anti-oxidative, antitumor, immunostimulatory and hypocholesterolemic properties when fed as dietary additive for farm animals. This article reviews and discusses the results of studies on the effects of dietary chitosan and its oligosaccharide derivatives on performance and metabolic response in poultry and pigs, that is, haematological, biochemical and immunological blood characteristics, microbiological profile of intestines, intestinal morphology and digestibility of nutrients, as well as on the quality of meat and eggs. The results of most of the experiments presented in this review indicate that chitosan used as a feed additive for poultry and pigs has some beneficial, biological effects, including immunomodulatory, anti-oxidative, antimicrobial and hypocholesterolemic properties. These properties of chitosan, unlike many other kinds of feed additives, were often reflected in improved growth performance (body weight gain and/or feed conversion ratio) of young animals, that is, broiler chickens and weaned pigs. PMID:25041091

  14. Preparation of a Novel Chitosan Based Biopolymer Dye and Application in Wood Dyeing

    Directory of Open Access Journals (Sweden)

    Xiaoqian Wang

    2016-09-01

    Full Text Available A novel chitosan-based biopolymer dye possessing antibacterial properties was synthesized by reaction of O-carboxymethyl chitosan and Acid Red GR. The synthesized materials were characterized by Fourier transform infrared spectroscopy (FTIR, degree of substitution (DS, X-ray photoelectron spectroscopy (XPS, thermogravimetric analysis (TG, X-ray diffraction (XRD, water solubility test, antibacterial property test, and dyeing performance, including dye uptake, color difference, and fastness. Results showed that the synthesized dye was combined by –NH3+ of O-carboxymethyl chitosan and the sulfonic group of Acid Red GR. According to the comprehensive analysis of XRD and water solubility, the introduction of the carboxymethyl group and acid dye molecule changed the structure of the chitosan from compact to loose, which improved the synthesized dye’s water solubility. However, the thermal stability of the synthesized dye was decreased. The antibacterial property of the poplar wood dyed with the synthesized dye was enhanced and its antibacterial rate, specifically against Staphylococcus aureus and Escherichia coli, also increased to a rate of more than 99%. However, the dye uptake of the synthesized dye was lower than that of the original dye. Despite this, though, the dyeing effect of the synthesized dye demonstrated better water-fastness, and light-fastness than the original dye. Therefore, the novel chitosan-based biopolymer dye can be a promising product for wood dyeing.

  15. Chitosan/TPP Nanoparticles as a Gene Delivery Agent For Tumor Suppressant P53

    Science.gov (United States)

    Liu, Gaojun

    In the last decade, non-viral polymeric vectors have become more attractive than their viral counterparts due to their nontoxicity and good biocompatibility. However, one of the major drawbacks is the low transfection efficiency when compared to viruses. In this work, a naturally cationic polysaccharide, chitosan, was cross-linked with negatively charged tripolyphosphate (TPP) to synthesize chitosan/TPP nanoparticles (CNPs) for delivery of plasmid DNA (pDNA). Particle size and zeta potential were characterized for CNPs with chitosan-TPP mass ratios of 4:1 and 6:1 (w/w) using benchtop dynamic light scattering. And both potentiometric titration method and FTIR spectrometer were applied to measure the degree of deacetylation of chitosan. Release kinetics of a model protein (bovine serum albumin, BSA) showed a steady release that reached 7% after 6 days. Besides that, we also assessed the in vitro transfection efficiency of the CNP-pDNA system using fluorescence microscopy, as well as the effect of tumor suppressant p53. Later the release kinetics and encapsulation efficiency of plasmid DNA bound to the CNPs will be investigated. Additionally, we will try to improve the gene transfection efficiency in both MC3T3-E1 and osteosarcoma cells by applying Sonicator 740 therapeutic ultrasound. Key words: gene therapy, non-viral gene vector, chitosan/TPP nanoparticles, ionic gelation, p53.

  16. Effects of Hypoxia and Chitosan on Equine Umbilical Cord-Derived Mesenchymal Stem Cells

    Directory of Open Access Journals (Sweden)

    D. J. Griffon

    2016-01-01

    Full Text Available Chitosan opens new perspectives in regenerative medicine as it enhances the properties of mesenchymal stem cells (MSCs through formation of spheroids. Hypoxia has also been proposed to enhance stemness and survival of MSCs after in vivo implantation. These characteristics are relevant to the development of an off-the-shelf source of allogenic cells for regenerative therapy of tendinopathies. Umbilical cord-derived MSCs (UCM-MSCs offer an abundant source of immature and immunoprivileged stem cells. In this study, equine UCM-MSCs (eqUCM-MSCs conditioned for 3 and 7 days on chitosan films at 5% oxygen were compared to eqUCM-MSCs under standard conditions. Equine UCM-MSCs formed spheroids on chitosan but yielded 72% less DNA than standard eqUCM-MSCs. Expression of Sox2, Oct4, and Nanog was 4 to 10 times greater in conditioned cells at day 7. Fluorescence-labeled cells cultured for 7 days under standard conditions or on chitosan films under hypoxia were compared in a bilateral patellar tendon defect model in rats. Fluorescence was present in all treated tendons, but the modulus of elasticity under tension was greater in tendons treated with conditioned cells. Chitosan and hypoxia affected cell yield but improved the stemness of eqUCM-MSCs and their contribution to the healing of tissues. Given the abundance of allogenic cells, these properties are highly relevant to clinical applications and outweigh the negative impact on cell proliferation.

  17. Antimicrobial Activities of Nisin, Tea Polyphenols, and Chitosan and their Combinations in Chilled Mutton.

    Science.gov (United States)

    He, Li; Zou, Likou; Yang, Qianru; Xia, Jinghua; Zhou, Kang; Zhu, Yuanting; Han, Xinfeng; Pu, Biao; Hu, Bin; Deng, Wenwen; Liu, Shuliang

    2016-06-01

    Antimicrobial activities of nisin, tea polyphenols (TPs), and chitosan, and their combinations were evaluated against both Gram-positive bacteria (GPB) and Gram-negative bacteria (GNB) by the agar dilution method. Results showed that the MIC of nisin was 2.44 to 1250 mg/L for GPB and reached 5000 mg/L for GNB. The MICs of TPs and chitosan were 313 to 625 mg/L and 469 mg/L for GNB, and 156 to 5000 mg/L and 234 to 938 mg/L for GPB, respectively. These results indicated that TPs and chitosan exhibited inhibitory effects against both GPB and GNB, whereas nisin inhibited the growth of GPB only. Based on the orthogonal test of their MICs, and evaluation of preservative effect and sensory attributes in chilled mutton, the optimum combination was chosen as 0.625, 0.313, and 3.752 g/L for nisin, TPs, and chitosan, respectively. By using the optimum treatment, the shelf life of chilled mutton was extended from 6 to 18 d at 4 °C in the preservative film packages. These results indicate that the combination of nisin, TPs, and chitosan could be used as preservatives to efficiently inhibit the growth of spoilage microorganisms and pathogens in meat, thus improving the safety and shelf life of chilled mutton. PMID:27096939

  18. Small angle Neutron Scatteringanalysis of chitosan in different phases

    International Nuclear Information System (INIS)

    Biopolymers are studied extensively due to its wide applications in the field of bio-technology, micro fluidics and lab on chip devices. Chitosan is natural biopolymer derived from chitin. It has wide applications in bio-medical engineering because of its biocompatibility and biodegradability. Also, chitosan act as reducing and stabilizing agent for the metal ions. Chitosan is also a good candidate in batteries as membranes. It is therefore important to study the conformational changes of chitosan. In this research work, we used SANS to understand the modifications in the radius of gyration (Rg) values of chitosan polymer in solution and in presence of HAuCl4 and LiClO4. Chitosan solution became a gel in the presence of HAuCl4 enabling to study the associated conformational change in chitosan in gels. We have also made films of chitosan, chitosan- Au and Chitosan- LiClO4 and studied the associated conformational changes in chitosan. Gels and films were formed by varying the concentration of HAuCl4. Lower concentration of HAuCl4 gave films while higher concentration of HAuCl4 gave gels. The Imaging was carried out for the samples using TEM and SEM. SANS shows that the chitosan solution (liquid) had greater Rg value than the chitosan film. The Rg value did not change in gels from that of solution. There was no correlation length for the fitting for chitosan in solution, however there was correlation length observed in the gels. This indicates that in gels the chitosan units are more localized than in solution phase. Interestingly, chitosan-Au-Li film shows the formation of star like structures which are not observed in case of gels. Hence we conclude that the presence of Lithium can induce conformational changes in chitosan films while HAuCl4 can localize chitosan units in solution leading to formation of gels.

  19. Status of Maize Technologies Adoption in Kisii Highlands of Kenya

    International Nuclear Information System (INIS)

    Maize is an important crop for the majority of the Kenyan population and is grown both in the low and high potential areas. It is grown by more than 90% of the smallholder farm families and is estimated to contribute more than 20% of the total agricultural production. Average maize yield in southwest Kenya is 2.5 t ha-1 which is far below the research achieved yields of 8 t ha-1. Farmers in the region have continued to grow maize under poor husbandry practices, minimal application of inputs and poor management. Formal and informal surveys were used for data gathering. The multi-stage sampling technique was used to sample survey units in Agroecological upper midland (UM1) and lower highland (LH1) both in the high potential areas of the region. Selected farmers were stratified according to resource base, sex of household head and the AEZ. Results indicated that components of maize technology package (varieties, inorganic fertilizers, pests/diseases, seedbed preparation and weed control) were at various stages of adoption. The most adopted components were use of improved hybrid seed, planting in rows and maintenance of recommended plant population. The most identified reason for non use of organic fertilizer was high cost. The limited use of inputs was aggravated by the liberalised state of inputs markets while the output market was imperfect and did not support the producer. Tough farmyard manure and compost are locally available alternatives, very few of the interviewed farmers used them. To further understand the adoption process, regression analysis of factors that influence the use of fertilizer on maize production was done. The results of the study will be used to improve and/or modify the existing technologies to conform to farmers' circumstances and needs as well as provide feedback to policy formulators

  20. Adsorption of Cadmium By Silica Chitosan

    OpenAIRE

    Moftah Ali; Ani Mulyasuryani; Akhmad Sabarudin

    2013-01-01

    The adsorption process depends on initial concentration of Cd2+ and ratio of  chitosan in adsorbent. The present study deals with the competitive adsorption of Cd2+ ion onto silica graft with chitosan. Batch adsorption experiments were performed at five different initial Cd2+ concentrations (5, 10, 15, 20 and 25 ppm), on five different proportion from silica to chitosan (100%, 95%, 85%, 75% and 65%) as adsorbent at pH 5. In the recovery process, the high recovery at 0.5 mg and observed the re...